<?xml version="1.0" encoding="us-ascii"?>
<!--Generated by Broadridge PROfile 24.3.1.5224 Broadridge-->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:t1="http://xbrl.org/2005/xbrldt">
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-roles-2023.xsd#eedm" />
  <link:roleRef roleURI="http://roivant.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SubsequentEventsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/NetIncomeLossPerCommonShareDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#NetIncomeLossPerCommonShareDetails" />
  <link:roleRef roleURI="http://roivant.com/role/FairValueMeasurementsFairValueOfSignificantUnobservableInputsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#FairValueMeasurementsFairValueOfSignificantUnobservableInputsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/FairValueMeasurementsChangesInFairValueOfLevel3LiabilitiesDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#FairValueMeasurementsChangesInFairValueOfLevel3LiabilitiesDetails" />
  <link:roleRef roleURI="http://roivant.com/role/FairValueMeasurementsChangesInFairValueOfLevel3AssetsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#FairValueMeasurementsChangesInFairValueOfLevel3AssetsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/FairValueMeasurementsAssetsAndLiabilitiesAreMeasuredAtFairValueOnRecurringBasisDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#FairValueMeasurementsAssetsAndLiabilitiesAreMeasuredAtFairValueOnRecurringBasisDetails" />
  <link:roleRef roleURI="http://roivant.com/role/EarnoutSharesPublicWarrantsAndPrivatePlacementWarrantsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#EarnoutSharesPublicWarrantsAndPrivatePlacementWarrantsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/CommitmentsAndContingenciesDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#CommitmentsAndContingenciesDetails" />
  <link:roleRef roleURI="http://roivant.com/role/LeasesMaturitiesOfOperatingLeaseLiabilitiesDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#LeasesMaturitiesOfOperatingLeaseLiabilitiesDetails" />
  <link:roleRef roleURI="http://roivant.com/role/LeasesOperatingLeaseRightofuseAssetsAndLeaseLiabilitiesDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#LeasesOperatingLeaseRightofuseAssetsAndLeaseLiabilitiesDetails" />
  <link:roleRef roleURI="http://roivant.com/role/LeasesComponentsOfOperatingLeaseExpenseDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#LeasesComponentsOfOperatingLeaseExpenseDetails" />
  <link:roleRef roleURI="http://roivant.com/role/IncomeTaxesSummaryDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#IncomeTaxesSummaryDetails" />
  <link:roleRef roleURI="http://roivant.com/role/IncomeTaxesDeferredTaxAssetsLiabilitiesDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#IncomeTaxesDeferredTaxAssetsLiabilitiesDetails" />
  <link:roleRef roleURI="http://roivant.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseBenefitDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#IncomeTaxesReconciliationOfIncomeTaxExpenseBenefitDetails" />
  <link:roleRef roleURI="http://roivant.com/role/IncomeTaxesIncomeTaxExpenseDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#IncomeTaxesIncomeTaxExpenseDetails" />
  <link:roleRef roleURI="http://roivant.com/role/IncomeTaxesIncomeLossBeforeIncomeTaxesAndRelatedExpenseBenefitDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#IncomeTaxesIncomeLossBeforeIncomeTaxesAndRelatedExpenseBenefitDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensationSubsidiaryEquityIncentivePlansDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensationSubsidiaryEquityIncentivePlansDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensationEmployeeStockPurchasePlanDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensationEmployeeStockPurchasePlanDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensationCvarsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensationCvarsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensationRestrictedStockUnitsAndPerformanceStockUnitsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensationRestrictedStockUnitsAndPerformanceStockUnitsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensationStockOptionsAndPerformanceStockOptionsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensationStockOptionsAndPerformanceStockOptionsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensationBlackscholesClosedFormOptionPricingModelDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensationBlackscholesClosedFormOptionPricingModelDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensationStockOptionsAndPerformanceStockOptionsUnderRslEquityPlansDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensationStockOptionsAndPerformanceStockOptionsUnderRslEquityPlansDetails" />
  <link:roleRef roleURI="http://roivant.com/role/ShareholdersEquityDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#ShareholdersEquityDetails" />
  <link:roleRef roleURI="http://roivant.com/role/DiscontinuedOperationsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#DiscontinuedOperationsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/LongtermDebtRevenueInterestPurchaseAndSaleAgreementDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#LongtermDebtRevenueInterestPurchaseAndSaleAgreementDetails" />
  <link:roleRef roleURI="http://roivant.com/role/LongtermDebtDermavantCreditFacilityWithXyqLuxcoDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#LongtermDebtDermavantCreditFacilityWithXyqLuxcoDetails" />
  <link:roleRef roleURI="http://roivant.com/role/LongtermDebtDermavantFundingAgreementWithNovaquestDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#LongtermDebtDermavantFundingAgreementWithNovaquestDetails" />
  <link:roleRef roleURI="http://roivant.com/role/CertainBalanceSheetComponentsOtherCurrentLiabilitiesDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#CertainBalanceSheetComponentsOtherCurrentLiabilitiesDetails" />
  <link:roleRef roleURI="http://roivant.com/role/CertainBalanceSheetComponentsAccruedExpensesDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#CertainBalanceSheetComponentsAccruedExpensesDetails" />
  <link:roleRef roleURI="http://roivant.com/role/CertainBalanceSheetComponentsOtherCurrentAssetsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#CertainBalanceSheetComponentsOtherCurrentAssetsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/RecentTransactionsAssetAcquisitionAndDeconsolidationOfSubsidiariesDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#RecentTransactionsAssetAcquisitionAndDeconsolidationOfSubsidiariesDetails" />
  <link:roleRef roleURI="http://roivant.com/role/RecentTransactionsTelavantDispositionDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#RecentTransactionsTelavantDispositionDetails" />
  <link:roleRef roleURI="http://roivant.com/role/IntangibleAssetsDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#IntangibleAssetsDetails" />
  <link:roleRef roleURI="http://roivant.com/role/EquityMethodInvestmentsSummarizedConsolidatedFinancialInformationDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#EquityMethodInvestmentsSummarizedConsolidatedFinancialInformationDetails" />
  <link:roleRef roleURI="http://roivant.com/role/EquityMethodInvestmentsSummarizedEquityMethodInvestmentDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#EquityMethodInvestmentsSummarizedEquityMethodInvestmentDetails" />
  <link:roleRef roleURI="http://roivant.com/role/EquityMethodInvestmentsInvestmentInArbutusDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#EquityMethodInvestmentsInvestmentInArbutusDetails" />
  <link:roleRef roleURI="http://roivant.com/role/RevenueDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#RevenueDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SummaryOfSignificantAccountingPoliciesPropertyAndEquipmentDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SummaryOfSignificantAccountingPoliciesPropertyAndEquipmentDetails" />
  <link:roleRef roleURI="http://roivant.com/role/SummaryOfSignificantAccountingPoliciesCashCashEquivalentsAndRestrictedCashDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#SummaryOfSignificantAccountingPoliciesCashCashEquivalentsAndRestrictedCashDetails" />
  <link:roleRef roleURI="http://roivant.com/role/DescriptionOfBusinessAndLiquidityDetails" xlink:type="simple" xlink:href="roiv-20240331.xsd#DescriptionOfBusinessAndLiquidityDetails" />
  <link:roleRef roleURI="http://roivant.com/role/NetIncomeLossPerCommonShareTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#NetIncomeLossPerCommonShareTables" />
  <link:roleRef roleURI="http://roivant.com/role/FairValueMeasurementsTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#FairValueMeasurementsTables" />
  <link:roleRef roleURI="http://roivant.com/role/LeasesTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#LeasesTables" />
  <link:roleRef roleURI="http://roivant.com/role/IncomeTaxesTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#IncomeTaxesTables" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensationTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensationTables" />
  <link:roleRef roleURI="http://roivant.com/role/DiscontinuedOperationsTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#DiscontinuedOperationsTables" />
  <link:roleRef roleURI="http://roivant.com/role/LongtermDebtTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#LongtermDebtTables" />
  <link:roleRef roleURI="http://roivant.com/role/CertainBalanceSheetComponentsTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#CertainBalanceSheetComponentsTables" />
  <link:roleRef roleURI="http://roivant.com/role/RecentTransactionsTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#RecentTransactionsTables" />
  <link:roleRef roleURI="http://roivant.com/role/IntangibleAssetsTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#IntangibleAssetsTables" />
  <link:roleRef roleURI="http://roivant.com/role/EquityMethodInvestmentsTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#EquityMethodInvestmentsTables" />
  <link:roleRef roleURI="http://roivant.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" xlink:href="roiv-20240331.xsd#SummaryOfSignificantAccountingPoliciesTables" />
  <link:roleRef roleURI="http://roivant.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" xlink:href="roiv-20240331.xsd#SummaryOfSignificantAccountingPoliciesPolicies" />
  <link:roleRef roleURI="http://roivant.com/role/SubsequentEvents" xlink:type="simple" xlink:href="roiv-20240331.xsd#SubsequentEvents" />
  <link:roleRef roleURI="http://roivant.com/role/NetIncomeLossPerCommonShare" xlink:type="simple" xlink:href="roiv-20240331.xsd#NetIncomeLossPerCommonShare" />
  <link:roleRef roleURI="http://roivant.com/role/FairValueMeasurements" xlink:type="simple" xlink:href="roiv-20240331.xsd#FairValueMeasurements" />
  <link:roleRef roleURI="http://roivant.com/role/EarnoutSharesPublicWarrantsAndPrivatePlacementWarrants" xlink:type="simple" xlink:href="roiv-20240331.xsd#EarnoutSharesPublicWarrantsAndPrivatePlacementWarrants" />
  <link:roleRef roleURI="http://roivant.com/role/CommitmentsAndContingencies" xlink:type="simple" xlink:href="roiv-20240331.xsd#CommitmentsAndContingencies" />
  <link:roleRef roleURI="http://roivant.com/role/Leases" xlink:type="simple" xlink:href="roiv-20240331.xsd#Leases" />
  <link:roleRef roleURI="http://roivant.com/role/IncomeTaxes" xlink:type="simple" xlink:href="roiv-20240331.xsd#IncomeTaxes" />
  <link:roleRef roleURI="http://roivant.com/role/SharebasedCompensation" xlink:type="simple" xlink:href="roiv-20240331.xsd#SharebasedCompensation" />
  <link:roleRef roleURI="http://roivant.com/role/ShareholdersEquity" xlink:type="simple" xlink:href="roiv-20240331.xsd#ShareholdersEquity" />
  <link:roleRef roleURI="http://roivant.com/role/DiscontinuedOperations" xlink:type="simple" xlink:href="roiv-20240331.xsd#DiscontinuedOperations" />
  <link:roleRef roleURI="http://roivant.com/role/LongtermDebt" xlink:type="simple" xlink:href="roiv-20240331.xsd#LongtermDebt" />
  <link:roleRef roleURI="http://roivant.com/role/CertainBalanceSheetComponents" xlink:type="simple" xlink:href="roiv-20240331.xsd#CertainBalanceSheetComponents" />
  <link:roleRef roleURI="http://roivant.com/role/RecentTransactions" xlink:type="simple" xlink:href="roiv-20240331.xsd#RecentTransactions" />
  <link:roleRef roleURI="http://roivant.com/role/IntangibleAssets" xlink:type="simple" xlink:href="roiv-20240331.xsd#IntangibleAssets" />
  <link:roleRef roleURI="http://roivant.com/role/EquityMethodInvestments" xlink:type="simple" xlink:href="roiv-20240331.xsd#EquityMethodInvestments" />
  <link:roleRef roleURI="http://roivant.com/role/Revenue" xlink:type="simple" xlink:href="roiv-20240331.xsd#Revenue" />
  <link:roleRef roleURI="http://roivant.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="simple" xlink:href="roiv-20240331.xsd#SummaryOfSignificantAccountingPolicies" />
  <link:roleRef roleURI="http://roivant.com/role/DescriptionOfBusinessAndLiquidity" xlink:type="simple" xlink:href="roiv-20240331.xsd#DescriptionOfBusinessAndLiquidity" />
  <link:roleRef roleURI="http://roivant.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="simple" xlink:href="roiv-20240331.xsd#ConsolidatedStatementsOfCashFlows" />
  <link:roleRef roleURI="http://roivant.com/role/ConsolidatedStatementsOfShareholdersEquityAndRedeemableNoncontrollingInterest" xlink:type="simple" xlink:href="roiv-20240331.xsd#ConsolidatedStatementsOfShareholdersEquityAndRedeemableNoncontrollingInterest" />
  <link:roleRef roleURI="http://roivant.com/role/ConsolidatedStatementsOfComprehensiveIncomeLoss" xlink:type="simple" xlink:href="roiv-20240331.xsd#ConsolidatedStatementsOfComprehensiveIncomeLoss" />
  <link:roleRef roleURI="http://roivant.com/role/ConsolidatedStatementsOfOperationsCalc2" xlink:type="simple" xlink:href="roiv-20240331.xsd#ConsolidatedStatementsOfOperationsCalc2" />
  <link:roleRef roleURI="http://roivant.com/role/ConsolidatedStatementsOfOperationsParenthetical" xlink:type="simple" xlink:href="roiv-20240331.xsd#ConsolidatedStatementsOfOperationsParenthetical" />
  <link:roleRef roleURI="http://roivant.com/role/ConsolidatedStatementsOfOperations" xlink:type="simple" xlink:href="roiv-20240331.xsd#ConsolidatedStatementsOfOperations" />
  <link:roleRef roleURI="http://roivant.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="roiv-20240331.xsd#ConsolidatedBalanceSheetsParenthetical" />
  <link:roleRef roleURI="http://roivant.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="roiv-20240331.xsd#ConsolidatedBalanceSheets" />
  <link:roleRef roleURI="http://roivant.com/role/DocumentAndEntityInformation" xlink:type="simple" xlink:href="roiv-20240331.xsd#DocumentAndEntityInformation" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/DocumentAndEntityInformation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ConsolidatedBalanceSheets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ConsolidatedBalanceSheetsParenthetical" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ConsolidatedStatementsOfOperations">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenuesAbstract" xlink:label="RevenuesAbstract" xlink:title="RevenuesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="RevenuesAbstract" xlink:title="definition: StatementLineItems to RevenuesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="OperatingExpensesAbstract" xlink:title="OperatingExpensesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingExpensesAbstract" xlink:title="definition: StatementLineItems to OperatingExpensesAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GainLossOnSaleOfAssets" xlink:label="GainLossOnSaleOfAssets" xlink:title="GainLossOnSaleOfAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="GainLossOnSaleOfAssets" xlink:title="definition: StatementLineItems to GainLossOnSaleOfAssets" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingIncomeLoss" xlink:title="definition: StatementLineItems to OperatingIncomeLoss" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainLossOnInvestments" xlink:label="GainLossOnInvestments" xlink:title="GainLossOnInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="GainLossOnInvestments" xlink:title="definition: StatementLineItems to GainLossOnInvestments" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GainLossOnFairValueOfDebtAndLiabilityInstruments" xlink:label="GainLossOnFairValueOfDebtAndLiabilityInstruments" xlink:title="GainLossOnFairValueOfDebtAndLiabilityInstruments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="GainLossOnFairValueOfDebtAndLiabilityInstruments" xlink:title="definition: StatementLineItems to GainLossOnFairValueOfDebtAndLiabilityInstruments" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeconsolidationGainOrLossAmount" xlink:label="DeconsolidationGainOrLossAmount" xlink:title="DeconsolidationGainOrLossAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DeconsolidationGainOrLossAmount" xlink:title="definition: StatementLineItems to DeconsolidationGainOrLossAmount" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_InterestIncome" xlink:label="InterestIncome" xlink:title="InterestIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="InterestIncome" xlink:title="definition: StatementLineItems to InterestIncome" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestExpense" xlink:label="InterestExpense" xlink:title="InterestExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="InterestExpense" xlink:title="definition: StatementLineItems to InterestExpense" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="OtherNonoperatingIncomeExpense" xlink:title="OtherNonoperatingIncomeExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherNonoperatingIncomeExpense" xlink:title="definition: StatementLineItems to OtherNonoperatingIncomeExpense" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="definition: StatementLineItems to IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="IncomeTaxExpenseBenefit" xlink:title="IncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeTaxExpenseBenefit" xlink:title="definition: StatementLineItems to IncomeTaxExpenseBenefit" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:label="IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:title="IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: StatementLineItems to IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:title="definition: StatementLineItems to IncomeLossFromDiscontinuedOperationsNetOfTax" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ProfitLoss" xlink:title="definition: StatementLineItems to ProfitLoss" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="NetIncomeLossAttributableToNoncontrollingInterest" xlink:title="NetIncomeLossAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetIncomeLossAttributableToNoncontrollingInterest" xlink:title="definition: StatementLineItems to NetIncomeLossAttributableToNoncontrollingInterest" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" xlink:title="NetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetIncomeLoss" xlink:title="definition: StatementLineItems to NetIncomeLoss" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeAmountsAttributableToReportingEntityDisclosuresAbstract" xlink:label="IncomeAmountsAttributableToReportingEntityDisclosuresAbstract" xlink:title="IncomeAmountsAttributableToReportingEntityDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeAmountsAttributableToReportingEntityDisclosuresAbstract" xlink:title="definition: StatementLineItems to IncomeAmountsAttributableToReportingEntityDisclosuresAbstract" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareBasicAbstract" xlink:label="EarningsPerShareBasicAbstract" xlink:title="EarningsPerShareBasicAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="EarningsPerShareBasicAbstract" xlink:title="definition: StatementLineItems to EarningsPerShareBasicAbstract" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareDilutedAbstract" xlink:label="EarningsPerShareDilutedAbstract" xlink:title="EarningsPerShareDilutedAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="EarningsPerShareDilutedAbstract" xlink:title="definition: StatementLineItems to EarningsPerShareDilutedAbstract" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:label="WeightedAverageNumberOfSharesOutstandingAbstract" xlink:title="WeightedAverageNumberOfSharesOutstandingAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="WeightedAverageNumberOfSharesOutstandingAbstract" xlink:title="definition: StatementLineItems to WeightedAverageNumberOfSharesOutstandingAbstract" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="WeightedAverageNumberOfSharesOutstandingBasic" xlink:title="WeightedAverageNumberOfSharesOutstandingBasic" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="WeightedAverageNumberOfSharesOutstandingBasic" xlink:title="definition: StatementLineItems to WeightedAverageNumberOfSharesOutstandingBasic" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="WeightedAverageNumberOfDilutedSharesOutstanding" xlink:title="WeightedAverageNumberOfDilutedSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="WeightedAverageNumberOfDilutedSharesOutstanding" xlink:title="definition: StatementLineItems to WeightedAverageNumberOfDilutedSharesOutstanding" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:label="IncomeLossFromContinuingOperationsPerDilutedShare" xlink:title="IncomeLossFromContinuingOperationsPerDilutedShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromContinuingOperationsPerDilutedShare" xlink:title="definition: StatementLineItems to IncomeLossFromContinuingOperationsPerDilutedShare" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:title="definition: StatementLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="EarningsPerShareDiluted" xlink:title="EarningsPerShareDiluted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="EarningsPerShareDiluted" xlink:title="definition: StatementLineItems to EarningsPerShareDiluted" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="IncomeLossFromContinuingOperationsPerBasicShare" xlink:title="IncomeLossFromContinuingOperationsPerBasicShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromContinuingOperationsPerBasicShare" xlink:title="definition: StatementLineItems to IncomeLossFromContinuingOperationsPerBasicShare" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:title="definition: StatementLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareBasic" xlink:label="EarningsPerShareBasic" xlink:title="EarningsPerShareBasic" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="EarningsPerShareBasic" xlink:title="definition: StatementLineItems to EarningsPerShareBasic" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperations" xlink:label="IncomeLossFromContinuingOperations" xlink:title="IncomeLossFromContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromContinuingOperations" xlink:title="definition: StatementLineItems to IncomeLossFromContinuingOperations" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:title="definition: StatementLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OperatingCosts" xlink:label="OperatingCosts" xlink:title="OperatingCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingCosts" xlink:title="definition: StatementLineItems to OperatingCosts" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="ResearchAndDevelopmentExpense" xlink:title="ResearchAndDevelopmentExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ResearchAndDevelopmentExpense" xlink:title="definition: StatementLineItems to ResearchAndDevelopmentExpense" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_AcquiredInProcessResearchAndDevelopmentExpense" xlink:label="AcquiredInProcessResearchAndDevelopmentExpense" xlink:title="AcquiredInProcessResearchAndDevelopmentExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AcquiredInProcessResearchAndDevelopmentExpense" xlink:title="definition: StatementLineItems to AcquiredInProcessResearchAndDevelopmentExpense" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="SellingGeneralAndAdministrativeExpense" xlink:title="SellingGeneralAndAdministrativeExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="SellingGeneralAndAdministrativeExpense" xlink:title="definition: StatementLineItems to SellingGeneralAndAdministrativeExpense" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingExpenses" xlink:label="OperatingExpenses" xlink:title="OperatingExpenses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingExpenses" xlink:title="definition: StatementLineItems to OperatingExpenses" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="definition: StatementLineItems to RevenueFromContractWithCustomerExcludingAssessedTax" order="37.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="38.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis" xlink:label="ProductOrServiceAxis" xlink:title="ProductOrServiceAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="ProductOrServiceAxis" xlink:title="definition: StatementTable to ProductOrServiceAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProductMember" xlink:label="ProductMember" xlink:title="ProductMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="ProductMember" xlink:title="definition: ProductsAndServicesDomain to ProductMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_LicenseMilestoneAndOtherRevenueMember" xlink:label="LicenseMilestoneAndOtherRevenueMember" xlink:title="LicenseMilestoneAndOtherRevenueMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="LicenseMilestoneAndOtherRevenueMember" xlink:title="definition: ProductsAndServicesDomain to LicenseMilestoneAndOtherRevenueMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ConsolidatedStatementsOfOperationsParenthetical">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensation" xlink:label="ShareBasedCompensation" xlink:title="ShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ShareBasedCompensation" xlink:title="definition: StatementLineItems to ShareBasedCompensation" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="IncomeStatementLocationAxis" xlink:title="IncomeStatementLocationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="IncomeStatementLocationAxis" xlink:title="definition: StatementTable to IncomeStatementLocationAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="IncomeStatementLocationDomain" xlink:title="IncomeStatementLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeStatementLocationAxis" xlink:to="IncomeStatementLocationDomain" xlink:title="definition: IncomeStatementLocationAxis to IncomeStatementLocationDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="IncomeStatementLocationDomain_2" xlink:title="IncomeStatementLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeStatementLocationAxis" xlink:to="IncomeStatementLocationDomain_2" xlink:title="definition: IncomeStatementLocationAxis to IncomeStatementLocationDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="ResearchAndDevelopmentExpenseMember" xlink:title="ResearchAndDevelopmentExpenseMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementLocationDomain" xlink:to="ResearchAndDevelopmentExpenseMember" xlink:title="definition: IncomeStatementLocationDomain to ResearchAndDevelopmentExpenseMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:label="SellingGeneralAndAdministrativeExpensesMember" xlink:title="SellingGeneralAndAdministrativeExpensesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementLocationDomain" xlink:to="SellingGeneralAndAdministrativeExpensesMember" xlink:title="definition: IncomeStatementLocationDomain to SellingGeneralAndAdministrativeExpensesMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ConsolidatedStatementsOfOperationsCalc2" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ConsolidatedStatementsOfComprehensiveIncomeLoss" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ConsolidatedStatementsOfShareholdersEquityAndRedeemableNoncontrollingInterest">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInTemporaryEquityRollForward" xlink:label="IncreaseDecreaseInTemporaryEquityRollForward" xlink:title="IncreaseDecreaseInTemporaryEquityRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncreaseDecreaseInTemporaryEquityRollForward" xlink:title="definition: StatementLineItems to IncreaseDecreaseInTemporaryEquityRollForward" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="IncreaseDecreaseInStockholdersEquityRollForward" xlink:title="IncreaseDecreaseInStockholdersEquityRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncreaseDecreaseInStockholdersEquityRollForward" xlink:title="definition: StatementLineItems to IncreaseDecreaseInStockholdersEquityRollForward" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: StatementLineItems to StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesOutstanding" xlink:label="SharesOutstanding" xlink:title="SharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="SharesOutstanding" xlink:title="definition: StatementLineItems to SharesOutstanding" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodValueNetIssuanceCosts" xlink:label="StockIssuedDuringPeriodValueNetIssuanceCosts" xlink:title="StockIssuedDuringPeriodValueNetIssuanceCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueNetIssuanceCosts" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueNetIssuanceCosts" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodSharesNetIssuanceCosts" xlink:label="StockIssuedDuringPeriodSharesNetIssuanceCosts" xlink:title="StockIssuedDuringPeriodSharesNetIssuanceCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesNetIssuanceCosts" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesNetIssuanceCosts" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" xlink:label="StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" xlink:title="StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" xlink:label="StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" xlink:title="StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansAndTaxWithholdingPayments" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" xlink:label="StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" xlink:title="StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" xlink:label="StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" xlink:title="StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesInConnectionWithEquityIncentivePlansNetOfForfeituresAndTaxWithholdingPayments" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsValue" xlink:label="StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsValue" xlink:title="StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsValue" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsValue" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsShares" xlink:label="StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsShares" xlink:title="StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsShares" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueCommonShareRelatedToSettlementOfWarrantsShares" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodValueCommonSharesRelatedToSettlementOfTransactionConsideration" xlink:label="StockIssuedDuringPeriodValueCommonSharesRelatedToSettlementOfTransactionConsideration" xlink:title="StockIssuedDuringPeriodValueCommonSharesRelatedToSettlementOfTransactionConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueCommonSharesRelatedToSettlementOfTransactionConsideration" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueCommonSharesRelatedToSettlementOfTransactionConsideration" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodSharesCommonSharesRelatedToSettlementOfTransactionConsideration" xlink:label="StockIssuedDuringPeriodSharesCommonSharesRelatedToSettlementOfTransactionConsideration" xlink:title="StockIssuedDuringPeriodSharesCommonSharesRelatedToSettlementOfTransactionConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesCommonSharesRelatedToSettlementOfTransactionConsideration" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesCommonSharesRelatedToSettlementOfTransactionConsideration" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:label="StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:title="StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:title="StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionValue" xlink:label="StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionValue" xlink:title="StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionValue" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionValue" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionShares" xlink:label="StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionShares" xlink:title="StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionShares" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodCommonSharesAndOtherConsiderationForAcquisitionShares" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IssuanceOfSubsidiaryCommonSharesToTheCompanyNetIssuanceCostsValue" xlink:label="IssuanceOfSubsidiaryCommonSharesToTheCompanyNetIssuanceCostsValue" xlink:title="IssuanceOfSubsidiaryCommonSharesToTheCompanyNetIssuanceCostsValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IssuanceOfSubsidiaryCommonSharesToTheCompanyNetIssuanceCostsValue" xlink:title="definition: StatementLineItems to IssuanceOfSubsidiaryCommonSharesToTheCompanyNetIssuanceCostsValue" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IssuanceOfSubsidiaryCommonSharesToTheCompanyShares" xlink:label="IssuanceOfSubsidiaryCommonSharesToTheCompanyShares" xlink:title="IssuanceOfSubsidiaryCommonSharesToTheCompanyShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IssuanceOfSubsidiaryCommonSharesToTheCompanyShares" xlink:title="definition: StatementLineItems to IssuanceOfSubsidiaryCommonSharesToTheCompanyShares" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodValueSubsidiaryStockOptionsExercised" xlink:label="StockIssuedDuringPeriodValueSubsidiaryStockOptionsExercised" xlink:title="StockIssuedDuringPeriodValueSubsidiaryStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueSubsidiaryStockOptionsExercised" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueSubsidiaryStockOptionsExercised" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IssuanceOfSubsidiaryCommonSharesToTheCompanyAndCapitalContributionsToSubsidiaries" xlink:label="IssuanceOfSubsidiaryCommonSharesToTheCompanyAndCapitalContributionsToSubsidiaries" xlink:title="IssuanceOfSubsidiaryCommonSharesToTheCompanyAndCapitalContributionsToSubsidiaries" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IssuanceOfSubsidiaryCommonSharesToTheCompanyAndCapitalContributionsToSubsidiaries" xlink:title="definition: StatementLineItems to IssuanceOfSubsidiaryCommonSharesToTheCompanyAndCapitalContributionsToSubsidiaries" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:label="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:title="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:title="definition: StatementLineItems to NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NoncontrollingInterestIncreaseDecreaseFromDeconsolidation" xlink:label="NoncontrollingInterestIncreaseDecreaseFromDeconsolidation" xlink:title="NoncontrollingInterestIncreaseDecreaseFromDeconsolidation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NoncontrollingInterestIncreaseDecreaseFromDeconsolidation" xlink:title="definition: StatementLineItems to NoncontrollingInterestIncreaseDecreaseFromDeconsolidation" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DividendDeclaredBySubsidiary" xlink:label="DividendDeclaredBySubsidiary" xlink:title="DividendDeclaredBySubsidiary" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DividendDeclaredBySubsidiary" xlink:title="definition: StatementLineItems to DividendDeclaredBySubsidiary" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NoncontrollingInterestIncreaseDecreaseFromDisposition" xlink:label="NoncontrollingInterestIncreaseDecreaseFromDisposition" xlink:title="NoncontrollingInterestIncreaseDecreaseFromDisposition" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NoncontrollingInterestIncreaseDecreaseFromDisposition" xlink:title="definition: StatementLineItems to NoncontrollingInterestIncreaseDecreaseFromDisposition" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognition" xlink:label="APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognition" xlink:title="APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognition" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognition" xlink:title="definition: StatementLineItems to APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognition" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognitionShares" xlink:label="APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognitionShares" xlink:title="APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognitionShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognitionShares" xlink:title="definition: StatementLineItems to APICAndNoncontrollingInterestShareBasedPaymentArrangementIncreaseForCostRecognitionShares" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:title="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:title="definition: StatementLineItems to OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ProfitLoss" xlink:title="definition: StatementLineItems to ProfitLoss" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests" xlink:label="TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests" xlink:title="TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests" xlink:title="definition: StatementLineItems to TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeconsolidationRevaluationOfRetainedInvestmentGainOrLossAmount" xlink:label="DeconsolidationRevaluationOfRetainedInvestmentGainOrLossAmount" xlink:title="DeconsolidationRevaluationOfRetainedInvestmentGainOrLossAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DeconsolidationRevaluationOfRetainedInvestmentGainOrLossAmount" xlink:title="definition: StatementLineItems to DeconsolidationRevaluationOfRetainedInvestmentGainOrLossAmount" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="33.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: StatementTable to StatementEquityComponentsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RedeemableNoncontrollingInterestMember" xlink:label="RedeemableNoncontrollingInterestMember" xlink:title="RedeemableNoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="RedeemableNoncontrollingInterestMember" xlink:title="definition: EquityComponentDomain to RedeemableNoncontrollingInterestMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="CommonStockMember" xlink:title="definition: EquityComponentDomain to CommonStockMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="AdditionalPaidInCapitalMember" xlink:title="AdditionalPaidInCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AdditionalPaidInCapitalMember" xlink:title="definition: EquityComponentDomain to AdditionalPaidInCapitalMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="AccumulatedOtherComprehensiveIncomeMember" xlink:title="AccumulatedOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedOtherComprehensiveIncomeMember" xlink:title="definition: EquityComponentDomain to AccumulatedOtherComprehensiveIncomeMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember" xlink:label="RetainedEarningsMember" xlink:title="RetainedEarningsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="RetainedEarningsMember" xlink:title="definition: EquityComponentDomain to RetainedEarningsMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="NoncontrollingInterestMember" xlink:title="NoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="NoncontrollingInterestMember" xlink:title="definition: EquityComponentDomain to NoncontrollingInterestMember" order="6.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ConsolidatedStatementsOfCashFlows" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/DescriptionOfBusinessAndLiquidity" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SummaryOfSignificantAccountingPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/Revenue" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/EquityMethodInvestments" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IntangibleAssets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/RecentTransactions" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/CertainBalanceSheetComponents" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LongtermDebt" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/DiscontinuedOperations" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ShareholdersEquity" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IncomeTaxes" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/Leases" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/CommitmentsAndContingencies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/EarnoutSharesPublicWarrantsAndPrivatePlacementWarrants" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/FairValueMeasurements" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/NetIncomeLossPerCommonShare" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SubsequentEvents" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SummaryOfSignificantAccountingPoliciesPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SummaryOfSignificantAccountingPoliciesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/EquityMethodInvestmentsTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="ScheduleOfEquityMethodInvestmentsLineItems" xlink:title="ScheduleOfEquityMethodInvestmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EquityMethodInvestmentSummarizedFinancialInformationTableTextBlock" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationTableTextBlock" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationTableTextBlock" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to EquityMethodInvestmentSummarizedFinancialInformationTableTextBlock" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="ScheduleOfEquityMethodInvestmentsTable" xlink:title="ScheduleOfEquityMethodInvestmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="ScheduleOfEquityMethodInvestmentsTable" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to ScheduleOfEquityMethodInvestmentsTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEquityMethodInvestmentsTable" xlink:to="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="definition: ScheduleOfEquityMethodInvestmentsTable to ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain_2" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain_2" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CioxParentMember" xlink:label="CioxParentMember" xlink:title="CioxParentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="CioxParentMember" xlink:title="definition: EquityMethodInvesteeNameDomain to CioxParentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ArbutusBiopharmaCorporationMember" xlink:label="ArbutusBiopharmaCorporationMember" xlink:title="ArbutusBiopharmaCorporationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="ArbutusBiopharmaCorporationMember" xlink:title="definition: EquityMethodInvesteeNameDomain to ArbutusBiopharmaCorporationMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IntangibleAssetsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/RecentTransactionsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/CertainBalanceSheetComponentsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LongtermDebtTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:label="ScheduleOfDebtInstrumentsTextBlock" xlink:title="ScheduleOfDebtInstrumentsTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ScheduleOfDebtInstrumentsTextBlock" xlink:title="definition: DebtInstrumentLineItems to ScheduleOfDebtInstrumentsTextBlock" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:label="ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:title="ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:title="definition: DebtInstrumentLineItems to ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: DebtInstrumentTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DermavantMember" xlink:label="DermavantMember" xlink:title="DermavantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DermavantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DermavantMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="TypeOfArrangementAxis" xlink:title="TypeOfArrangementAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="TypeOfArrangementAxis" xlink:title="definition: DebtInstrumentTable to TypeOfArrangementAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FundingAgreementWithNovaQuestMember" xlink:label="FundingAgreementWithNovaQuestMember" xlink:title="FundingAgreementWithNovaQuestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="FundingAgreementWithNovaQuestMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to FundingAgreementWithNovaQuestMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CreditFacilityWithXYQLuxcoMember" xlink:label="CreditFacilityWithXYQLuxcoMember" xlink:title="CreditFacilityWithXYQLuxcoMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="CreditFacilityWithXYQLuxcoMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to CreditFacilityWithXYQLuxcoMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:label="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:title="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/DiscontinuedOperationsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensationTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ScheduleOfShareBasedCompensationStockOptionsAndPerformanceOptionsActivityTableTextBlock" xlink:label="ScheduleOfShareBasedCompensationStockOptionsAndPerformanceOptionsActivityTableTextBlock" xlink:title="ScheduleOfShareBasedCompensationStockOptionsAndPerformanceOptionsActivityTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationStockOptionsAndPerformanceOptionsActivityTableTextBlock" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationStockOptionsAndPerformanceOptionsActivityTableTextBlock" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:label="ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:title="ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ScheduleOfShareBasedPaymentArrangementFairValueOfVestedStockOptionAndPerformanceOptionTableTextBlock" xlink:label="ScheduleOfShareBasedPaymentArrangementFairValueOfVestedStockOptionAndPerformanceOptionTableTextBlock" xlink:title="ScheduleOfShareBasedPaymentArrangementFairValueOfVestedStockOptionAndPerformanceOptionTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedPaymentArrangementFairValueOfVestedStockOptionAndPerformanceOptionTableTextBlock" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedPaymentArrangementFairValueOfVestedStockOptionAndPerformanceOptionTableTextBlock" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ScheduleOfShareBasedCompensationRestrictedStockAndPerformanceStockUnitsAwardActivityTableTextBlock" xlink:label="ScheduleOfShareBasedCompensationRestrictedStockAndPerformanceStockUnitsAwardActivityTableTextBlock" xlink:title="ScheduleOfShareBasedCompensationRestrictedStockAndPerformanceStockUnitsAwardActivityTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationRestrictedStockAndPerformanceStockUnitsAwardActivityTableTextBlock" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationRestrictedStockAndPerformanceStockUnitsAwardActivityTableTextBlock" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ScheduleOfCappedValueAppreciationRightsStockUnitsActivityTableTextBlock" xlink:label="ScheduleOfCappedValueAppreciationRightsStockUnitsActivityTableTextBlock" xlink:title="ScheduleOfCappedValueAppreciationRightsStockUnitsActivityTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfCappedValueAppreciationRightsStockUnitsActivityTableTextBlock" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfCappedValueAppreciationRightsStockUnitsActivityTableTextBlock" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CappedValueAppreciationRightsMember" xlink:label="CappedValueAppreciationRightsMember" xlink:title="CappedValueAppreciationRightsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="CappedValueAppreciationRightsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to CappedValueAppreciationRightsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis" xlink:label="PlanNameAxis" xlink:title="PlanNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="PlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to PlanNameAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain" xlink:title="definition: PlanNameAxis to PlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain_2" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain_2" xlink:title="definition: PlanNameAxis to PlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EquityIncentivePlan2015Member" xlink:label="EquityIncentivePlan2015Member" xlink:title="EquityIncentivePlan2015Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="EquityIncentivePlan2015Member" xlink:title="definition: PlanNameDomain to EquityIncentivePlan2015Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EquityIncentivePlan2021Member" xlink:label="EquityIncentivePlan2021Member" xlink:title="EquityIncentivePlan2021Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="EquityIncentivePlan2021Member" xlink:title="definition: PlanNameDomain to EquityIncentivePlan2021Member" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IncomeTaxesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LeasesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/FairValueMeasurementsTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:label="ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:title="ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" xlink:label="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" xlink:title="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" xlink:label="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" xlink:title="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTableTextBlock" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain_2" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain_2" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DatavantHoldingsIncMember" xlink:label="DatavantHoldingsIncMember" xlink:title="DatavantHoldingsIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="DatavantHoldingsIncMember" xlink:title="definition: EquityMethodInvesteeNameDomain to DatavantHoldingsIncMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to StatementEquityComponentsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnoutSharesMember" xlink:label="EarnoutSharesMember" xlink:title="EarnoutSharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="EarnoutSharesMember" xlink:title="definition: EquityComponentDomain to EarnoutSharesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="ClassOfWarrantOrRightAxis" xlink:title="ClassOfWarrantOrRightAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="ClassOfWarrantOrRightAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to ClassOfWarrantOrRightAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain_2" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain_2" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PrivatePlacementWarrantsMember" xlink:label="PrivatePlacementWarrantsMember" xlink:title="PrivatePlacementWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="PrivatePlacementWarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to PrivatePlacementWarrantsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/NetIncomeLossPerCommonShareTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/DescriptionOfBusinessAndLiquidityDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="ScheduleOfEquityMethodInvestmentsLineItems" xlink:title="ScheduleOfEquityMethodInvestmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DescriptionOfBusinessAbstract" xlink:label="DescriptionOfBusinessAbstract" xlink:title="DescriptionOfBusinessAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="DescriptionOfBusinessAbstract" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to DescriptionOfBusinessAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_LiquidityAbstract" xlink:label="LiquidityAbstract" xlink:title="LiquidityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="LiquidityAbstract" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to LiquidityAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GainLossOnSaleOfAssets" xlink:label="GainLossOnSaleOfAssets" xlink:title="GainLossOnSaleOfAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="GainLossOnSaleOfAssets" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to GainLossOnSaleOfAssets" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="CashAndCashEquivalentsAtCarryingValue" xlink:title="CashAndCashEquivalentsAtCarryingValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="CashAndCashEquivalentsAtCarryingValue" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to CashAndCashEquivalentsAtCarryingValue" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="RetainedEarningsAccumulatedDeficit" xlink:title="RetainedEarningsAccumulatedDeficit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="RetainedEarningsAccumulatedDeficit" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to RetainedEarningsAccumulatedDeficit" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:label="IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:title="IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MinimumAgeRequiredForTreatment" xlink:label="MinimumAgeRequiredForTreatment" xlink:title="MinimumAgeRequiredForTreatment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="MinimumAgeRequiredForTreatment" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to MinimumAgeRequiredForTreatment" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="NumberOfOperatingSegments" xlink:title="NumberOfOperatingSegments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="NumberOfOperatingSegments" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to NumberOfOperatingSegments" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NumberOfReportableSegments" xlink:label="NumberOfReportableSegments" xlink:title="NumberOfReportableSegments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="NumberOfReportableSegments" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to NumberOfReportableSegments" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="ScheduleOfEquityMethodInvestmentsTable" xlink:title="ScheduleOfEquityMethodInvestmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="ScheduleOfEquityMethodInvestmentsTable" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to ScheduleOfEquityMethodInvestmentsTable" order="10.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="SubsequentEventTypeAxis" xlink:title="SubsequentEventTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEquityMethodInvestmentsTable" xlink:to="SubsequentEventTypeAxis" xlink:title="definition: ScheduleOfEquityMethodInvestmentsTable to SubsequentEventTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="SubsequentEventTypeDomain" xlink:title="SubsequentEventTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SubsequentEventTypeAxis" xlink:to="SubsequentEventTypeDomain" xlink:title="definition: SubsequentEventTypeAxis to SubsequentEventTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="SubsequentEventTypeDomain_2" xlink:title="SubsequentEventTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SubsequentEventTypeAxis" xlink:to="SubsequentEventTypeDomain_2" xlink:title="definition: SubsequentEventTypeAxis to SubsequentEventTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventMember" xlink:label="SubsequentEventMember" xlink:title="SubsequentEventMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventTypeDomain" xlink:to="SubsequentEventMember" xlink:title="definition: SubsequentEventTypeDomain to SubsequentEventMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEquityMethodInvestmentsTable" xlink:to="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="definition: ScheduleOfEquityMethodInvestmentsTable to ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain_2" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain_2" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_TelavantHoldingsIncMember" xlink:label="TelavantHoldingsIncMember" xlink:title="TelavantHoldingsIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="TelavantHoldingsIncMember" xlink:title="definition: EquityMethodInvesteeNameDomain to TelavantHoldingsIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SummaryOfSignificantAccountingPoliciesCashCashEquivalentsAndRestrictedCashDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SummaryOfSignificantAccountingPoliciesPropertyAndEquipmentDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="PropertyPlantAndEquipmentLineItems" xlink:title="PropertyPlantAndEquipmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PropertyAndEquipmentsAbstract" xlink:label="PropertyAndEquipmentsAbstract" xlink:title="PropertyAndEquipmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyAndEquipmentsAbstract" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyAndEquipmentsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="PropertyPlantAndEquipmentUsefulLife" xlink:title="PropertyPlantAndEquipmentUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentUsefulLife" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentUsefulLife" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="ScheduleOfPropertyPlantAndEquipmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ScheduleOfPropertyPlantAndEquipmentTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="PropertyPlantAndEquipmentByTypeAxis" xlink:title="PropertyPlantAndEquipmentByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="PropertyPlantAndEquipmentByTypeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to PropertyPlantAndEquipmentByTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ComputerEquipmentMember" xlink:label="ComputerEquipmentMember" xlink:title="ComputerEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="ComputerEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to ComputerEquipmentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquipmentMember" xlink:label="EquipmentMember" xlink:title="EquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="EquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to EquipmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="FurnitureAndFixturesMember" xlink:title="FurnitureAndFixturesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="FurnitureAndFixturesMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to FurnitureAndFixturesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SoftwareDevelopmentMember" xlink:label="SoftwareDevelopmentMember" xlink:title="SoftwareDevelopmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="SoftwareDevelopmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to SoftwareDevelopmentMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/RevenueDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="DisaggregationOfRevenueLineItems" xlink:title="DisaggregationOfRevenueLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_LicenseMilestoneAndOtherRevenueAbstract" xlink:label="LicenseMilestoneAndOtherRevenueAbstract" xlink:title="LicenseMilestoneAndOtherRevenueAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="LicenseMilestoneAndOtherRevenueAbstract" xlink:title="definition: DisaggregationOfRevenueLineItems to LicenseMilestoneAndOtherRevenueAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NonRefundableUpfrontPaymentReceived" xlink:label="NonRefundableUpfrontPaymentReceived" xlink:title="NonRefundableUpfrontPaymentReceived" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="NonRefundableUpfrontPaymentReceived" xlink:title="definition: DisaggregationOfRevenueLineItems to NonRefundableUpfrontPaymentReceived" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PotentialMilestonePaymentReceivable" xlink:label="PotentialMilestonePaymentReceivable" xlink:title="PotentialMilestonePaymentReceivable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="PotentialMilestonePaymentReceivable" xlink:title="definition: DisaggregationOfRevenueLineItems to PotentialMilestonePaymentReceivable" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MilestonePaymentsAmountReceived" xlink:label="MilestonePaymentsAmountReceived" xlink:title="MilestonePaymentsAmountReceived" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="MilestonePaymentsAmountReceived" xlink:title="definition: DisaggregationOfRevenueLineItems to MilestonePaymentsAmountReceived" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="definition: DisaggregationOfRevenueLineItems to RevenueFromContractWithCustomerExcludingAssessedTax" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="DisaggregationOfRevenueTable" xlink:title="DisaggregationOfRevenueTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisaggregationOfRevenueLineItems" xlink:to="DisaggregationOfRevenueTable" xlink:title="definition: DisaggregationOfRevenueLineItems to DisaggregationOfRevenueTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisaggregationOfRevenueTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: DisaggregationOfRevenueTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CovantMember" xlink:label="CovantMember" xlink:title="CovantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="CovantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to CovantMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DermavantMember" xlink:label="DermavantMember" xlink:title="DermavantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DermavantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DermavantMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GenevantMember" xlink:label="GenevantMember" xlink:title="GenevantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="GenevantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to GenevantMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="TypeOfArrangementAxis" xlink:title="TypeOfArrangementAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisaggregationOfRevenueTable" xlink:to="TypeOfArrangementAxis" xlink:title="definition: DisaggregationOfRevenueTable to TypeOfArrangementAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CollaborationAndLicenseAgreementMember" xlink:label="CollaborationAndLicenseAgreementMember" xlink:title="CollaborationAndLicenseAgreementMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="CollaborationAndLicenseAgreementMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to CollaborationAndLicenseAgreementMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis" xlink:label="ProductOrServiceAxis" xlink:title="ProductOrServiceAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisaggregationOfRevenueTable" xlink:to="ProductOrServiceAxis" xlink:title="definition: DisaggregationOfRevenueTable to ProductOrServiceAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_LicenseMilestoneAndOtherRevenueMember" xlink:label="LicenseMilestoneAndOtherRevenueMember" xlink:title="LicenseMilestoneAndOtherRevenueMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="LicenseMilestoneAndOtherRevenueMember" xlink:title="definition: ProductsAndServicesDomain to LicenseMilestoneAndOtherRevenueMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/EquityMethodInvestmentsInvestmentInArbutusDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="ScheduleOfEquityMethodInvestmentsLineItems" xlink:title="ScheduleOfEquityMethodInvestmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_InvestmentsDisclosureAbstract" xlink:label="InvestmentsDisclosureAbstract" xlink:title="InvestmentsDisclosureAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="InvestmentsDisclosureAbstract" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to InvestmentsDisclosureAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="CommonStockSharesOutstanding" xlink:title="CommonStockSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="CommonStockSharesOutstanding" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to CommonStockSharesOutstanding" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="ScheduleOfEquityMethodInvestmentsTable" xlink:title="ScheduleOfEquityMethodInvestmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="ScheduleOfEquityMethodInvestmentsTable" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to ScheduleOfEquityMethodInvestmentsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEquityMethodInvestmentsTable" xlink:to="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="definition: ScheduleOfEquityMethodInvestmentsTable to ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain_2" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain_2" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ArbutusBiopharmaCorporationMember" xlink:label="ArbutusBiopharmaCorporationMember" xlink:title="ArbutusBiopharmaCorporationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="ArbutusBiopharmaCorporationMember" xlink:title="definition: EquityMethodInvesteeNameDomain to ArbutusBiopharmaCorporationMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEquityMethodInvestmentsTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: ScheduleOfEquityMethodInvestmentsTable to StatementEquityComponentsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="CommonStockMember" xlink:title="definition: EquityComponentDomain to CommonStockMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/EquityMethodInvestmentsSummarizedEquityMethodInvestmentDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="ScheduleOfEquityMethodInvestmentsLineItems" xlink:title="ScheduleOfEquityMethodInvestmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SignificantEquityMethodInvestmentsAbstract" xlink:label="SignificantEquityMethodInvestmentsAbstract" xlink:title="SignificantEquityMethodInvestmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="SignificantEquityMethodInvestmentsAbstract" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to SignificantEquityMethodInvestmentsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_UnrealizedLossesGainsOnSignificantEquityMethodInvestmentsAbstract" xlink:label="UnrealizedLossesGainsOnSignificantEquityMethodInvestmentsAbstract" xlink:title="UnrealizedLossesGainsOnSignificantEquityMethodInvestmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="UnrealizedLossesGainsOnSignificantEquityMethodInvestmentsAbstract" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to UnrealizedLossesGainsOnSignificantEquityMethodInvestmentsAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrealizedGainLossOnInvestments" xlink:label="UnrealizedGainLossOnInvestments" xlink:title="UnrealizedGainLossOnInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="UnrealizedGainLossOnInvestments" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to UnrealizedGainLossOnInvestments" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="EquityMethodInvestmentOwnershipPercentage" xlink:title="EquityMethodInvestmentOwnershipPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="EquityMethodInvestmentOwnershipPercentage" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to EquityMethodInvestmentOwnershipPercentage" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestmentsFairValueDisclosure" xlink:label="InvestmentsFairValueDisclosure" xlink:title="InvestmentsFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="InvestmentsFairValueDisclosure" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to InvestmentsFairValueDisclosure" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="ScheduleOfEquityMethodInvestmentsTable" xlink:title="ScheduleOfEquityMethodInvestmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="ScheduleOfEquityMethodInvestmentsTable" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to ScheduleOfEquityMethodInvestmentsTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEquityMethodInvestmentsTable" xlink:to="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="definition: ScheduleOfEquityMethodInvestmentsTable to ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain_2" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain_2" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CioxParentMember" xlink:label="CioxParentMember" xlink:title="CioxParentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="CioxParentMember" xlink:title="definition: EquityMethodInvesteeNameDomain to CioxParentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ArbutusBiopharmaCorporationMember" xlink:label="ArbutusBiopharmaCorporationMember" xlink:title="ArbutusBiopharmaCorporationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="ArbutusBiopharmaCorporationMember" xlink:title="definition: EquityMethodInvesteeNameDomain to ArbutusBiopharmaCorporationMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/EquityMethodInvestmentsSummarizedConsolidatedFinancialInformationDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="ScheduleOfEquityMethodInvestmentsLineItems" xlink:title="ScheduleOfEquityMethodInvestmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementAbstract" xlink:label="IncomeStatementAbstract" xlink:title="IncomeStatementAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="IncomeStatementAbstract" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to IncomeStatementAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="RevenueFromContractWithCustomerExcludingAssessedTax" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to RevenueFromContractWithCustomerExcludingAssessedTax" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GrossProfit" xlink:label="GrossProfit" xlink:title="GrossProfit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="GrossProfit" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to GrossProfit" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="OperatingIncomeLoss" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to OperatingIncomeLoss" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="ProfitLoss" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to ProfitLoss" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="ScheduleOfEquityMethodInvestmentsTable" xlink:title="ScheduleOfEquityMethodInvestmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="ScheduleOfEquityMethodInvestmentsTable" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to ScheduleOfEquityMethodInvestmentsTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis" xlink:label="EquityMethodInvestmentNonconsolidatedInvesteeAxis" xlink:title="EquityMethodInvestmentNonconsolidatedInvesteeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEquityMethodInvestmentsTable" xlink:to="EquityMethodInvestmentNonconsolidatedInvesteeAxis" xlink:title="definition: ScheduleOfEquityMethodInvestmentsTable to EquityMethodInvestmentNonconsolidatedInvesteeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain" xlink:label="EquityMethodInvestmentNonconsolidatedInvesteeDomain" xlink:title="EquityMethodInvestmentNonconsolidatedInvesteeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="EquityMethodInvestmentNonconsolidatedInvesteeAxis" xlink:to="EquityMethodInvestmentNonconsolidatedInvesteeDomain" xlink:title="definition: EquityMethodInvestmentNonconsolidatedInvesteeAxis to EquityMethodInvestmentNonconsolidatedInvesteeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain" xlink:label="EquityMethodInvestmentNonconsolidatedInvesteeDomain_2" xlink:title="EquityMethodInvestmentNonconsolidatedInvesteeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="EquityMethodInvestmentNonconsolidatedInvesteeAxis" xlink:to="EquityMethodInvestmentNonconsolidatedInvesteeDomain_2" xlink:title="definition: EquityMethodInvestmentNonconsolidatedInvesteeAxis to EquityMethodInvestmentNonconsolidatedInvesteeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CioxParentMember" xlink:label="CioxParentMember" xlink:title="CioxParentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvestmentNonconsolidatedInvesteeDomain" xlink:to="CioxParentMember" xlink:title="definition: EquityMethodInvestmentNonconsolidatedInvesteeDomain to CioxParentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ArbutusBiopharmaCorporationMember" xlink:label="ArbutusBiopharmaCorporationMember" xlink:title="ArbutusBiopharmaCorporationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvestmentNonconsolidatedInvesteeDomain" xlink:to="ArbutusBiopharmaCorporationMember" xlink:title="definition: EquityMethodInvestmentNonconsolidatedInvesteeDomain to ArbutusBiopharmaCorporationMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:label="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:title="AcquiredFiniteLivedIntangibleAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IntangibleAssetAbstract" xlink:label="IntangibleAssetAbstract" xlink:title="IntangibleAssetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="IntangibleAssetAbstract" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to IntangibleAssetAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MilestonePayable" xlink:label="MilestonePayable" xlink:title="MilestonePayable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="MilestonePayable" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to MilestonePayable" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MilestonePaid" xlink:label="MilestonePaid" xlink:title="MilestonePaid" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="MilestonePaid" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to MilestonePaid" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNetAbstract" xlink:label="FiniteLivedIntangibleAssetsNetAbstract" xlink:title="FiniteLivedIntangibleAssetsNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsNetAbstract" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsNetAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="AmortizationOfIntangibleAssets" xlink:title="AmortizationOfIntangibleAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="AmortizationOfIntangibleAssets" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to AmortizationOfIntangibleAssets" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="FiniteLivedIntangibleAssetsGross" xlink:title="FiniteLivedIntangibleAssetsGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsGross" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsGross" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:title="FiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAccumulatedAmortization" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="IntangibleAssetsNetExcludingGoodwill" xlink:title="IntangibleAssetsNetExcludingGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="IntangibleAssetsNetExcludingGoodwill" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to IntangibleAssetsNetExcludingGoodwill" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:label="ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:title="ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:to="ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsLineItems to ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" order="15.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CounterpartyNameAxis" xlink:label="CounterpartyNameAxis" xlink:title="CounterpartyNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:to="CounterpartyNameAxis" xlink:title="definition: ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable to CounterpartyNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="RepurchaseAgreementCounterpartyNameDomain" xlink:title="RepurchaseAgreementCounterpartyNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="CounterpartyNameAxis" xlink:to="RepurchaseAgreementCounterpartyNameDomain" xlink:title="definition: CounterpartyNameAxis to RepurchaseAgreementCounterpartyNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="RepurchaseAgreementCounterpartyNameDomain_2" xlink:title="RepurchaseAgreementCounterpartyNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CounterpartyNameAxis" xlink:to="RepurchaseAgreementCounterpartyNameDomain_2" xlink:title="definition: CounterpartyNameAxis to RepurchaseAgreementCounterpartyNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GlaxoSmithKlineIntellectualPropertyDevelopmentLtdMember" xlink:label="GlaxoSmithKlineIntellectualPropertyDevelopmentLtdMember" xlink:title="GlaxoSmithKlineIntellectualPropertyDevelopmentLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RepurchaseAgreementCounterpartyNameDomain" xlink:to="GlaxoSmithKlineIntellectualPropertyDevelopmentLtdMember" xlink:title="definition: RepurchaseAgreementCounterpartyNameDomain to GlaxoSmithKlineIntellectualPropertyDevelopmentLtdMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_WelichemBiotechIncMember" xlink:label="WelichemBiotechIncMember" xlink:title="WelichemBiotechIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RepurchaseAgreementCounterpartyNameDomain" xlink:to="WelichemBiotechIncMember" xlink:title="definition: RepurchaseAgreementCounterpartyNameDomain to WelichemBiotechIncMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="IncomeStatementLocationAxis" xlink:title="IncomeStatementLocationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:to="IncomeStatementLocationAxis" xlink:title="definition: ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable to IncomeStatementLocationAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="IncomeStatementLocationDomain" xlink:title="IncomeStatementLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeStatementLocationAxis" xlink:to="IncomeStatementLocationDomain" xlink:title="definition: IncomeStatementLocationAxis to IncomeStatementLocationDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="IncomeStatementLocationDomain_2" xlink:title="IncomeStatementLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeStatementLocationAxis" xlink:to="IncomeStatementLocationDomain_2" xlink:title="definition: IncomeStatementLocationAxis to IncomeStatementLocationDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostOfSalesMember" xlink:label="CostOfSalesMember" xlink:title="CostOfSalesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementLocationDomain" xlink:to="CostOfSalesMember" xlink:title="definition: IncomeStatementLocationDomain to CostOfSalesMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/RecentTransactionsTelavantDispositionDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DisposalGroupAbstract" xlink:label="DisposalGroupAbstract" xlink:title="DisposalGroupAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupAbstract" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionConsiderationTransferred" xlink:label="AssetAcquisitionConsiderationTransferred" xlink:title="AssetAcquisitionConsiderationTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="AssetAcquisitionConsiderationTransferred" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to AssetAcquisitionConsiderationTransferred" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_AssetAcquisitionResearchAndDevelopmentExpenseInProcess" xlink:label="AssetAcquisitionResearchAndDevelopmentExpenseInProcess" xlink:title="AssetAcquisitionResearchAndDevelopmentExpenseInProcess" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="AssetAcquisitionResearchAndDevelopmentExpenseInProcess" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to AssetAcquisitionResearchAndDevelopmentExpenseInProcess" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OwnershipOfSubsidiaryPercentage" xlink:label="OwnershipOfSubsidiaryPercentage" xlink:title="OwnershipOfSubsidiaryPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="OwnershipOfSubsidiaryPercentage" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to OwnershipOfSubsidiaryPercentage" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DisposalGroupsIncludingDiscontinuedOperationsCalculationOfGainAbstract" xlink:label="DisposalGroupsIncludingDiscontinuedOperationsCalculationOfGainAbstract" xlink:title="DisposalGroupsIncludingDiscontinuedOperationsCalculationOfGainAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupsIncludingDiscontinuedOperationsCalculationOfGainAbstract" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupsIncludingDiscontinuedOperationsCalculationOfGainAbstract" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IncomeLossFromDisposalGroupBeforeIncomeTax" xlink:label="IncomeLossFromDisposalGroupBeforeIncomeTax" xlink:title="IncomeLossFromDisposalGroupBeforeIncomeTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeLossFromDisposalGroupBeforeIncomeTax" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeLossFromDisposalGroupBeforeIncomeTax" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DisposalGroupConsiderationAbstract" xlink:label="DisposalGroupConsiderationAbstract" xlink:title="DisposalGroupConsiderationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupConsiderationAbstract" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupConsiderationAbstract" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DisposalGroupAssets" xlink:label="DisposalGroupAssets" xlink:title="DisposalGroupAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupAssets" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupAssets" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DisposalGroupLiabilities" xlink:label="DisposalGroupLiabilities" xlink:title="DisposalGroupLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupLiabilities" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupLiabilities" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DisposalGroupNetAssetsLiabilities" xlink:label="DisposalGroupNetAssetsLiabilities" xlink:title="DisposalGroupNetAssetsLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupNetAssetsLiabilities" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupNetAssetsLiabilities" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GainLossOnSaleOfAssets" xlink:label="GainLossOnSaleOfAssets" xlink:title="GainLossOnSaleOfAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="GainLossOnSaleOfAssets" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to GainLossOnSaleOfAssets" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_UpfrontCashPaymentReceivedForSaleOfAssets" xlink:label="UpfrontCashPaymentReceivedForSaleOfAssets" xlink:title="UpfrontCashPaymentReceivedForSaleOfAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="UpfrontCashPaymentReceivedForSaleOfAssets" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to UpfrontCashPaymentReceivedForSaleOfAssets" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FutureMilestoneToBeReceivedFromSaleOfAssets" xlink:label="FutureMilestoneToBeReceivedFromSaleOfAssets" xlink:title="FutureMilestoneToBeReceivedFromSaleOfAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="FutureMilestoneToBeReceivedFromSaleOfAssets" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to FutureMilestoneToBeReceivedFromSaleOfAssets" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DisposalGroupNoncontrollingInterestDerecognizedValue" xlink:label="DisposalGroupNoncontrollingInterestDerecognizedValue" xlink:title="DisposalGroupNoncontrollingInterestDerecognizedValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupNoncontrollingInterestDerecognizedValue" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupNoncontrollingInterestDerecognizedValue" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ConsiderationReceivedForSaleOfAssets" xlink:label="ConsiderationReceivedForSaleOfAssets" xlink:title="ConsiderationReceivedForSaleOfAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="ConsiderationReceivedForSaleOfAssets" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to ConsiderationReceivedForSaleOfAssets" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" order="16.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable to IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:title="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis to DisposalGroupsIncludingDiscontinuedOperationsNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" xlink:title="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis to DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_TelavantHoldingsIncMember" xlink:label="TelavantHoldingsIncMember" xlink:title="TelavantHoldingsIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="TelavantHoldingsIncMember" xlink:title="definition: DisposalGroupsIncludingDiscontinuedOperationsNameDomain to TelavantHoldingsIncMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RocheTransactionMember" xlink:label="RocheTransactionMember" xlink:title="RocheTransactionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="RocheTransactionMember" xlink:title="definition: DisposalGroupsIncludingDiscontinuedOperationsNameDomain to RocheTransactionMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable to StatementEquityComponentsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RSLMember" xlink:label="RSLMember" xlink:title="RSLMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="RSLMember" xlink:title="definition: EquityComponentDomain to RSLMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PfizerMember" xlink:label="PfizerMember" xlink:title="PfizerMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="PfizerMember" xlink:title="definition: EquityComponentDomain to PfizerMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/RecentTransactionsAssetAcquisitionAndDeconsolidationOfSubsidiariesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionLineItems" xlink:label="AssetAcquisitionLineItems" xlink:title="AssetAcquisitionLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionAbstract" xlink:label="AssetAcquisitionAbstract" xlink:title="AssetAcquisitionAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="AssetAcquisitionAbstract" xlink:title="definition: AssetAcquisitionLineItems to AssetAcquisitionAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DeconsolidationOfSubsidiariesAbstract" xlink:label="DeconsolidationOfSubsidiariesAbstract" xlink:title="DeconsolidationOfSubsidiariesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="DeconsolidationOfSubsidiariesAbstract" xlink:title="definition: AssetAcquisitionLineItems to DeconsolidationOfSubsidiariesAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsForRepurchaseOfPreferredStockAndPreferenceStock" xlink:label="PaymentsForRepurchaseOfPreferredStockAndPreferenceStock" xlink:title="PaymentsForRepurchaseOfPreferredStockAndPreferenceStock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="PaymentsForRepurchaseOfPreferredStockAndPreferenceStock" xlink:title="definition: AssetAcquisitionLineItems to PaymentsForRepurchaseOfPreferredStockAndPreferenceStock" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOrSaleOfEquity" xlink:label="ProceedsFromIssuanceOrSaleOfEquity" xlink:title="ProceedsFromIssuanceOrSaleOfEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="ProceedsFromIssuanceOrSaleOfEquity" xlink:title="definition: AssetAcquisitionLineItems to ProceedsFromIssuanceOrSaleOfEquity" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeconsolidationGainOrLossAmount" xlink:label="DeconsolidationGainOrLossAmount" xlink:title="DeconsolidationGainOrLossAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="DeconsolidationGainOrLossAmount" xlink:title="definition: AssetAcquisitionLineItems to DeconsolidationGainOrLossAmount" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestmentsFairValueDisclosure" xlink:label="InvestmentsFairValueDisclosure" xlink:title="InvestmentsFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="InvestmentsFairValueDisclosure" xlink:title="definition: AssetAcquisitionLineItems to InvestmentsFairValueDisclosure" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_UpfrontCashPayment" xlink:label="UpfrontCashPayment" xlink:title="UpfrontCashPayment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="UpfrontCashPayment" xlink:title="definition: AssetAcquisitionLineItems to UpfrontCashPayment" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_AssetAcquisitionResearchAndDevelopmentExpenseInProcess" xlink:label="AssetAcquisitionResearchAndDevelopmentExpenseInProcess" xlink:title="AssetAcquisitionResearchAndDevelopmentExpenseInProcess" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="AssetAcquisitionResearchAndDevelopmentExpenseInProcess" xlink:title="definition: AssetAcquisitionLineItems to AssetAcquisitionResearchAndDevelopmentExpenseInProcess" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MilestonePaymentPayable" xlink:label="MilestonePaymentPayable" xlink:title="MilestonePaymentPayable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetAcquisitionLineItems" xlink:to="MilestonePaymentPayable" xlink:title="definition: AssetAcquisitionLineItems to MilestonePaymentPayable" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetAcquisitionTable" xlink:label="AssetAcquisitionTable" xlink:title="AssetAcquisitionTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="AssetAcquisitionLineItems" xlink:to="AssetAcquisitionTable" xlink:title="definition: AssetAcquisitionLineItems to AssetAcquisitionTable" order="10.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="SubsidiarySaleOfStockAxis" xlink:title="SubsidiarySaleOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="AssetAcquisitionTable" xlink:to="SubsidiarySaleOfStockAxis" xlink:title="definition: AssetAcquisitionTable to SubsidiarySaleOfStockAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="SaleOfStockNameOfTransactionDomain" xlink:title="SaleOfStockNameOfTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SubsidiarySaleOfStockAxis" xlink:to="SaleOfStockNameOfTransactionDomain" xlink:title="definition: SubsidiarySaleOfStockAxis to SaleOfStockNameOfTransactionDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="SaleOfStockNameOfTransactionDomain_2" xlink:title="SaleOfStockNameOfTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SubsidiarySaleOfStockAxis" xlink:to="SaleOfStockNameOfTransactionDomain_2" xlink:title="definition: SubsidiarySaleOfStockAxis to SaleOfStockNameOfTransactionDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_VantAIPreferredFinancingMember" xlink:label="VantAIPreferredFinancingMember" xlink:title="VantAIPreferredFinancingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="VantAIPreferredFinancingMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to VantAIPreferredFinancingMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="AssetAcquisitionTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: AssetAcquisitionTable to RelatedPartyTransactionsByRelatedPartyAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SKIncMember" xlink:label="SKIncMember" xlink:title="SKIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="SKIncMember" xlink:title="definition: RelatedPartyDomain to SKIncMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SKBiopharmaceuticalsCoLtdMember" xlink:label="SKBiopharmaceuticalsCoLtdMember" xlink:title="SKBiopharmaceuticalsCoLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="SKBiopharmaceuticalsCoLtdMember" xlink:title="definition: RelatedPartyDomain to SKBiopharmaceuticalsCoLtdMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="AssetAcquisitionTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: AssetAcquisitionTable to BusinessAcquisitionAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ProteovantSciencesIncMember" xlink:label="ProteovantSciencesIncMember" xlink:title="ProteovantSciencesIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="ProteovantSciencesIncMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to ProteovantSciencesIncMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NewlyFormedSubsidiaryMember" xlink:label="NewlyFormedSubsidiaryMember" xlink:title="NewlyFormedSubsidiaryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="NewlyFormedSubsidiaryMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to NewlyFormedSubsidiaryMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="AssetAcquisitionTable" xlink:to="RangeAxis" xlink:title="definition: AssetAcquisitionTable to RangeAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/CertainBalanceSheetComponentsOtherCurrentAssetsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/CertainBalanceSheetComponentsAccruedExpensesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/CertainBalanceSheetComponentsOtherCurrentLiabilitiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LongtermDebtDermavantFundingAgreementWithNovaquestDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FundingAgreementWithNovaQuestAbstract" xlink:label="FundingAgreementWithNovaQuestAbstract" xlink:title="FundingAgreementWithNovaQuestAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="FundingAgreementWithNovaQuestAbstract" xlink:title="definition: DebtInstrumentLineItems to FundingAgreementWithNovaQuestAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtCurrentAndNoncurrentAbstract" xlink:label="LongtermDebtCurrentAndNoncurrentAbstract" xlink:title="LongtermDebtCurrentAndNoncurrentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongtermDebtCurrentAndNoncurrentAbstract" xlink:title="definition: DebtInstrumentLineItems to LongtermDebtCurrentAndNoncurrentAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFairValue" xlink:label="DebtInstrumentFairValue" xlink:title="DebtInstrumentFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentFairValue" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentFairValue" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShorttermDebtFairValue" xlink:label="ShorttermDebtFairValue" xlink:title="ShorttermDebtFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ShorttermDebtFairValue" xlink:title="definition: DebtInstrumentLineItems to ShorttermDebtFairValue" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtFairValue" xlink:label="LongTermDebtFairValue" xlink:title="LongTermDebtFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtFairValue" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtFairValue" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="DebtInstrumentFaceAmount" xlink:title="DebtInstrumentFaceAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentFaceAmount" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentFaceAmount" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfDebt" xlink:label="ProceedsFromIssuanceOfDebt" xlink:title="ProceedsFromIssuanceOfDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ProceedsFromIssuanceOfDebt" xlink:title="definition: DebtInstrumentLineItems to ProceedsFromIssuanceOfDebt" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFrequencyOfPeriodicPayment" xlink:label="DebtInstrumentFrequencyOfPeriodicPayment" xlink:title="DebtInstrumentFrequencyOfPeriodicPayment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentFrequencyOfPeriodicPayment" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentFrequencyOfPeriodicPayment" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MilestonePaymentDueOverSixYearPeriod" xlink:label="MilestonePaymentDueOverSixYearPeriod" xlink:title="MilestonePaymentDueOverSixYearPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="MilestonePaymentDueOverSixYearPeriod" xlink:title="definition: DebtInstrumentLineItems to MilestonePaymentDueOverSixYearPeriod" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MaximumMilestonePaymentObligation" xlink:label="MaximumMilestonePaymentObligation" xlink:title="MaximumMilestonePaymentObligation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="MaximumMilestonePaymentObligation" xlink:title="definition: DebtInstrumentLineItems to MaximumMilestonePaymentObligation" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTerm" xlink:label="DebtInstrumentTerm" xlink:title="DebtInstrumentTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTerm" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTerm" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MaximumMilestonePaymentOffsetAmount" xlink:label="MaximumMilestonePaymentOffsetAmount" xlink:title="MaximumMilestonePaymentOffsetAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="MaximumMilestonePaymentOffsetAmount" xlink:title="definition: DebtInstrumentLineItems to MaximumMilestonePaymentOffsetAmount" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DebtInstrumentQuarterlyPaymentsMade" xlink:label="DebtInstrumentQuarterlyPaymentsMade" xlink:title="DebtInstrumentQuarterlyPaymentsMade" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentQuarterlyPaymentsMade" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentQuarterlyPaymentsMade" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" order="14.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: DebtInstrumentTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DermavantMember" xlink:label="DermavantMember" xlink:title="DermavantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DermavantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DermavantMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="TypeOfArrangementAxis" xlink:title="TypeOfArrangementAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="TypeOfArrangementAxis" xlink:title="definition: DebtInstrumentTable to TypeOfArrangementAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FundingAgreementWithNovaQuestMember" xlink:label="FundingAgreementWithNovaQuestMember" xlink:title="FundingAgreementWithNovaQuestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="FundingAgreementWithNovaQuestMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to FundingAgreementWithNovaQuestMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="RestructuringCostAndReserveAxis" xlink:title="RestructuringCostAndReserveAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="RestructuringCostAndReserveAxis" xlink:title="definition: DebtInstrumentTable to RestructuringCostAndReserveAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="TypeOfRestructuringDomain" xlink:title="TypeOfRestructuringDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RestructuringCostAndReserveAxis" xlink:to="TypeOfRestructuringDomain" xlink:title="definition: RestructuringCostAndReserveAxis to TypeOfRestructuringDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="TypeOfRestructuringDomain_2" xlink:title="TypeOfRestructuringDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RestructuringCostAndReserveAxis" xlink:to="TypeOfRestructuringDomain_2" xlink:title="definition: RestructuringCostAndReserveAxis to TypeOfRestructuringDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractTerminationMember" xlink:label="ContractTerminationMember" xlink:title="ContractTerminationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypeOfRestructuringDomain" xlink:to="ContractTerminationMember" xlink:title="definition: TypeOfRestructuringDomain to ContractTerminationMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="RangeAxis" xlink:title="definition: DebtInstrumentTable to RangeAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="StatementScenarioAxis" xlink:title="definition: DebtInstrumentTable to StatementScenarioAxis" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain_2" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain_2" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioForecastMember" xlink:label="ScenarioForecastMember" xlink:title="ScenarioForecastMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScenarioUnspecifiedDomain" xlink:to="ScenarioForecastMember" xlink:title="definition: ScenarioUnspecifiedDomain to ScenarioForecastMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LongtermDebtDermavantCreditFacilityWithXyqLuxcoDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_LoanAndCreditAgreementsByDermavantAbstract" xlink:label="LoanAndCreditAgreementsByDermavantAbstract" xlink:title="LoanAndCreditAgreementsByDermavantAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LoanAndCreditAgreementsByDermavantAbstract" xlink:title="definition: DebtInstrumentLineItems to LoanAndCreditAgreementsByDermavantAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:label="ProceedsFromLinesOfCredit" xlink:title="ProceedsFromLinesOfCredit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ProceedsFromLinesOfCredit" xlink:title="definition: DebtInstrumentLineItems to ProceedsFromLinesOfCredit" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTerm" xlink:label="DebtInstrumentTerm" xlink:title="DebtInstrumentTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTerm" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTerm" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="DebtInstrumentInterestRateStatedPercentage" xlink:title="DebtInstrumentInterestRateStatedPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentInterestRateStatedPercentage" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentInterestRateStatedPercentage" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DebtInstrumentExitFeeAndEndOfTermCharge" xlink:label="DebtInstrumentExitFeeAndEndOfTermCharge" xlink:title="DebtInstrumentExitFeeAndEndOfTermCharge" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentExitFeeAndEndOfTermCharge" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentExitFeeAndEndOfTermCharge" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFeeAmount" xlink:label="DebtInstrumentFeeAmount" xlink:title="DebtInstrumentFeeAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentFeeAmount" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentFeeAmount" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" xlink:label="ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" xlink:title="ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" xlink:title="definition: DebtInstrumentLineItems to ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:title="ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:title="definition: DebtInstrumentLineItems to ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtAbstract" xlink:label="LongTermDebtAbstract" xlink:title="LongTermDebtAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtAbstract" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtAbstract" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtByMaturityAbstract" xlink:label="LongTermDebtByMaturityAbstract" xlink:title="LongTermDebtByMaturityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtByMaturityAbstract" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtByMaturityAbstract" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DebtInstrumentCarryingAmountIncludingExitFee" xlink:label="DebtInstrumentCarryingAmountIncludingExitFee" xlink:title="DebtInstrumentCarryingAmountIncludingExitFee" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentCarryingAmountIncludingExitFee" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentCarryingAmountIncludingExitFee" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="DebtInstrumentCarryingAmount" xlink:title="DebtInstrumentCarryingAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentCarryingAmount" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentCarryingAmount" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DebtInstrumentExitFee" xlink:label="DebtInstrumentExitFee" xlink:title="DebtInstrumentExitFee" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentExitFee" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentExitFee" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:label="DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:title="DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebt" xlink:label="LongTermDebt" xlink:title="LongTermDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebt" xlink:title="definition: DebtInstrumentLineItems to LongTermDebt" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtCurrent" xlink:label="LongTermDebtCurrent" xlink:title="LongTermDebtCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtCurrent" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtCurrent" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="LongTermDebtNoncurrent" xlink:title="LongTermDebtNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtNoncurrent" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtNoncurrent" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" order="24.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: DebtInstrumentTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DermavantMember" xlink:label="DermavantMember" xlink:title="DermavantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DermavantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DermavantMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="TypeOfArrangementAxis" xlink:title="TypeOfArrangementAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="TypeOfArrangementAxis" xlink:title="definition: DebtInstrumentTable to TypeOfArrangementAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CreditFacilityWithXYQLuxcoMember" xlink:label="CreditFacilityWithXYQLuxcoMember" xlink:title="CreditFacilityWithXYQLuxcoMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="CreditFacilityWithXYQLuxcoMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to CreditFacilityWithXYQLuxcoMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LongtermDebtRevenueInterestPurchaseAndSaleAgreementDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RevenueInterestPurchaseAndSaleAgreementAbstract" xlink:label="RevenueInterestPurchaseAndSaleAgreementAbstract" xlink:title="RevenueInterestPurchaseAndSaleAgreementAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="RevenueInterestPurchaseAndSaleAgreementAbstract" xlink:title="definition: DebtInstrumentLineItems to RevenueInterestPurchaseAndSaleAgreementAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreement" xlink:label="CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreement" xlink:title="CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreement" xlink:title="definition: DebtInstrumentLineItems to CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreement" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CommittedFundingUnderRIPSA" xlink:label="CommittedFundingUnderRIPSA" xlink:title="CommittedFundingUnderRIPSA" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CommittedFundingUnderRIPSA" xlink:title="definition: DebtInstrumentLineItems to CommittedFundingUnderRIPSA" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreementReceived" xlink:label="CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreementReceived" xlink:title="CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreementReceived" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreementReceived" xlink:title="definition: DebtInstrumentLineItems to CommittedFundingUnderRevenueInterestPurchaseAndSaleAgreementReceived" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtAbstract" xlink:label="LongTermDebtAbstract" xlink:title="LongTermDebtAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtAbstract" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtAbstract" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="DebtInstrumentCarryingAmount" xlink:title="DebtInstrumentCarryingAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentCarryingAmount" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentCarryingAmount" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:label="DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:title="DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebt" xlink:label="LongTermDebt" xlink:title="LongTermDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebt" xlink:title="definition: DebtInstrumentLineItems to LongTermDebt" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtCurrent" xlink:label="LongTermDebtCurrent" xlink:title="LongTermDebtCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtCurrent" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtCurrent" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="LongTermDebtNoncurrent" xlink:title="LongTermDebtNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtNoncurrent" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtNoncurrent" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" order="11.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: DebtInstrumentTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DermavantMember" xlink:label="DermavantMember" xlink:title="DermavantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DermavantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DermavantMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="TypeOfArrangementAxis" xlink:title="TypeOfArrangementAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="TypeOfArrangementAxis" xlink:title="definition: DebtInstrumentTable to TypeOfArrangementAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:label="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:title="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/DiscontinuedOperationsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MyovantTransactionAbstract" xlink:label="MyovantTransactionAbstract" xlink:title="MyovantTransactionAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="MyovantTransactionAbstract" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to MyovantTransactionAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInDiscontinuedOperationsAbstract" xlink:label="NetCashProvidedByUsedInDiscontinuedOperationsAbstract" xlink:title="NetCashProvidedByUsedInDiscontinuedOperationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="NetCashProvidedByUsedInDiscontinuedOperationsAbstract" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to NetCashProvidedByUsedInDiscontinuedOperationsAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GainLossOnRecoveryOfContingentConsiderationDiscontinuedOperations" xlink:label="GainLossOnRecoveryOfContingentConsiderationDiscontinuedOperations" xlink:title="GainLossOnRecoveryOfContingentConsiderationDiscontinuedOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="GainLossOnRecoveryOfContingentConsiderationDiscontinuedOperations" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to GainLossOnRecoveryOfContingentConsiderationDiscontinuedOperations" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ProceedsFromSaleOfTopUpSharesDiscontinuedOperations" xlink:label="ProceedsFromSaleOfTopUpSharesDiscontinuedOperations" xlink:title="ProceedsFromSaleOfTopUpSharesDiscontinuedOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="ProceedsFromSaleOfTopUpSharesDiscontinuedOperations" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to ProceedsFromSaleOfTopUpSharesDiscontinuedOperations" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharePrice" xlink:label="SharePrice" xlink:title="SharePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="SharePrice" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to SharePrice" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NumberOfTopUpSharesReceived" xlink:label="NumberOfTopUpSharesReceived" xlink:title="NumberOfTopUpSharesReceived" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="NumberOfTopUpSharesReceived" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to NumberOfTopUpSharesReceived" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NumberOfVants" xlink:label="NumberOfVants" xlink:title="NumberOfVants" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="NumberOfVants" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to NumberOfVants" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable to IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:title="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis to DisposalGroupsIncludingDiscontinuedOperationsNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" xlink:title="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis to DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MyovantSciencesLtdMember" xlink:label="MyovantSciencesLtdMember" xlink:title="MyovantSciencesLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="MyovantSciencesLtdMember" xlink:title="definition: DisposalGroupsIncludingDiscontinuedOperationsNameDomain to MyovantSciencesLtdMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RSLMember" xlink:label="RSLMember" xlink:title="RSLMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="RSLMember" xlink:title="definition: DisposalGroupsIncludingDiscontinuedOperationsNameDomain to RSLMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="DisposalGroupClassificationAxis" xlink:title="DisposalGroupClassificationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="DisposalGroupClassificationAxis" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable to DisposalGroupClassificationAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="DisposalGroupClassificationDomain" xlink:title="DisposalGroupClassificationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DisposalGroupClassificationAxis" xlink:to="DisposalGroupClassificationDomain" xlink:title="definition: DisposalGroupClassificationAxis to DisposalGroupClassificationDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="DisposalGroupClassificationDomain_2" xlink:title="DisposalGroupClassificationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DisposalGroupClassificationAxis" xlink:to="DisposalGroupClassificationDomain_2" xlink:title="definition: DisposalGroupClassificationAxis to DisposalGroupClassificationDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDiscontinuedOperationsMember" xlink:label="SegmentDiscontinuedOperationsMember" xlink:title="SegmentDiscontinuedOperationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisposalGroupClassificationDomain" xlink:to="SegmentDiscontinuedOperationsMember" xlink:title="definition: DisposalGroupClassificationDomain to SegmentDiscontinuedOperationsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable to StatementEquityComponentsAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="CommonStockMember" xlink:title="definition: EquityComponentDomain to CommonStockMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/ShareholdersEquityDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockLineItems" xlink:label="ClassOfStockLineItems" xlink:title="ClassOfStockLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityNoteAbstract" xlink:label="StockholdersEquityNoteAbstract" xlink:title="StockholdersEquityNoteAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockholdersEquityNoteAbstract" xlink:title="definition: ClassOfStockLineItems to StockholdersEquityNoteAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CommonSharesOfferingPriceAuthorized" xlink:label="CommonSharesOfferingPriceAuthorized" xlink:title="CommonSharesOfferingPriceAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="CommonSharesOfferingPriceAuthorized" xlink:title="definition: ClassOfStockLineItems to CommonSharesOfferingPriceAuthorized" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CommonSharesAggregateOfferingPriceAuthorizedRemainingCapacityAvailable" xlink:label="CommonSharesAggregateOfferingPriceAuthorizedRemainingCapacityAvailable" xlink:title="CommonSharesAggregateOfferingPriceAuthorizedRemainingCapacityAvailable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="CommonSharesAggregateOfferingPriceAuthorizedRemainingCapacityAvailable" xlink:title="definition: ClassOfStockLineItems to CommonSharesAggregateOfferingPriceAuthorizedRemainingCapacityAvailable" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="StockIssuedDuringPeriodSharesNewIssues" xlink:title="StockIssuedDuringPeriodSharesNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockIssuedDuringPeriodSharesNewIssues" xlink:title="definition: ClassOfStockLineItems to StockIssuedDuringPeriodSharesNewIssues" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedAndSoldUponExerciseOfTheUnderwritersOption" xlink:label="StockIssuedAndSoldUponExerciseOfTheUnderwritersOption" xlink:title="StockIssuedAndSoldUponExerciseOfTheUnderwritersOption" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockIssuedAndSoldUponExerciseOfTheUnderwritersOption" xlink:title="definition: ClassOfStockLineItems to StockIssuedAndSoldUponExerciseOfTheUnderwritersOption" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharePrice" xlink:label="SharePrice" xlink:title="SharePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="SharePrice" xlink:title="definition: ClassOfStockLineItems to SharePrice" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockSoldDuringPeriodBySellingShareholders" xlink:label="StockSoldDuringPeriodBySellingShareholders" xlink:title="StockSoldDuringPeriodBySellingShareholders" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockSoldDuringPeriodBySellingShareholders" xlink:title="definition: ClassOfStockLineItems to StockSoldDuringPeriodBySellingShareholders" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="ProceedsFromIssuanceOfCommonStock" xlink:title="ProceedsFromIssuanceOfCommonStock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="ProceedsFromIssuanceOfCommonStock" xlink:title="definition: ClassOfStockLineItems to ProceedsFromIssuanceOfCommonStock" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockPricePerShare" xlink:label="SaleOfStockPricePerShare" xlink:title="SaleOfStockPricePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="SaleOfStockPricePerShare" xlink:title="definition: ClassOfStockLineItems to SaleOfStockPricePerShare" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NetProceedsFromIssuanceOfCommonStock" xlink:label="NetProceedsFromIssuanceOfCommonStock" xlink:title="NetProceedsFromIssuanceOfCommonStock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="NetProceedsFromIssuanceOfCommonStock" xlink:title="definition: ClassOfStockLineItems to NetProceedsFromIssuanceOfCommonStock" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeconsolidationGainOrLossAmount" xlink:label="DeconsolidationGainOrLossAmount" xlink:title="DeconsolidationGainOrLossAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="DeconsolidationGainOrLossAmount" xlink:title="definition: ClassOfStockLineItems to DeconsolidationGainOrLossAmount" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockPurchasedDuringPeriodByEntityShares" xlink:label="StockPurchasedDuringPeriodByEntityShares" xlink:title="StockPurchasedDuringPeriodByEntityShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockPurchasedDuringPeriodByEntityShares" xlink:title="definition: ClassOfStockLineItems to StockPurchasedDuringPeriodByEntityShares" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OptionToPurchaseAdditionalSharesOfCommonStock" xlink:label="OptionToPurchaseAdditionalSharesOfCommonStock" xlink:title="OptionToPurchaseAdditionalSharesOfCommonStock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="OptionToPurchaseAdditionalSharesOfCommonStock" xlink:title="definition: ClassOfStockLineItems to OptionToPurchaseAdditionalSharesOfCommonStock" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EstimatedNetProceedsFromIssuanceOfCommonStock" xlink:label="EstimatedNetProceedsFromIssuanceOfCommonStock" xlink:title="EstimatedNetProceedsFromIssuanceOfCommonStock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="EstimatedNetProceedsFromIssuanceOfCommonStock" xlink:title="definition: ClassOfStockLineItems to EstimatedNetProceedsFromIssuanceOfCommonStock" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OwnershipOfSubsidiaryPercentage" xlink:label="OwnershipOfSubsidiaryPercentage" xlink:title="OwnershipOfSubsidiaryPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="OwnershipOfSubsidiaryPercentage" xlink:title="definition: ClassOfStockLineItems to OwnershipOfSubsidiaryPercentage" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="ScheduleOfStockByClassTable" xlink:title="ScheduleOfStockByClassTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ClassOfStockLineItems" xlink:to="ScheduleOfStockByClassTable" xlink:title="definition: ClassOfStockLineItems to ScheduleOfStockByClassTable" order="16.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="RelatedPartyTransactionAxis" xlink:title="RelatedPartyTransactionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="RelatedPartyTransactionAxis" xlink:title="definition: ScheduleOfStockByClassTable to RelatedPartyTransactionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="RelatedPartyTransactionDomain" xlink:title="RelatedPartyTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionAxis" xlink:to="RelatedPartyTransactionDomain" xlink:title="definition: RelatedPartyTransactionAxis to RelatedPartyTransactionDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="RelatedPartyTransactionDomain_2" xlink:title="RelatedPartyTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionAxis" xlink:to="RelatedPartyTransactionDomain_2" xlink:title="definition: RelatedPartyTransactionAxis to RelatedPartyTransactionDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CowenAndCompanyLLCMember" xlink:label="CowenAndCompanyLLCMember" xlink:title="CowenAndCompanyLLCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionDomain" xlink:to="CowenAndCompanyLLCMember" xlink:title="definition: RelatedPartyTransactionDomain to CowenAndCompanyLLCMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CantorFitzgeraldCo.Member" xlink:label="CantorFitzgeraldCo.Member" xlink:title="CantorFitzgeraldCo.Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionDomain" xlink:to="CantorFitzgeraldCo.Member" xlink:title="definition: RelatedPartyTransactionDomain to CantorFitzgeraldCo.Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CytovantMember" xlink:label="CytovantMember" xlink:title="CytovantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionDomain" xlink:to="CytovantMember" xlink:title="definition: RelatedPartyTransactionDomain to CytovantMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="SubsidiarySaleOfStockAxis" xlink:title="SubsidiarySaleOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="SubsidiarySaleOfStockAxis" xlink:title="definition: ScheduleOfStockByClassTable to SubsidiarySaleOfStockAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="SaleOfStockNameOfTransactionDomain" xlink:title="SaleOfStockNameOfTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SubsidiarySaleOfStockAxis" xlink:to="SaleOfStockNameOfTransactionDomain" xlink:title="definition: SubsidiarySaleOfStockAxis to SaleOfStockNameOfTransactionDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="SaleOfStockNameOfTransactionDomain_2" xlink:title="SaleOfStockNameOfTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SubsidiarySaleOfStockAxis" xlink:to="SaleOfStockNameOfTransactionDomain_2" xlink:title="definition: SubsidiarySaleOfStockAxis to SaleOfStockNameOfTransactionDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EquityOfferingsAtTheMarketMember" xlink:label="EquityOfferingsAtTheMarketMember" xlink:title="EquityOfferingsAtTheMarketMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="EquityOfferingsAtTheMarketMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to EquityOfferingsAtTheMarketMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_UnderwrittenPublicOfferingMember" xlink:label="UnderwrittenPublicOfferingMember" xlink:title="UnderwrittenPublicOfferingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="UnderwrittenPublicOfferingMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to UnderwrittenPublicOfferingMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SoldByRSLMember" xlink:label="SoldByRSLMember" xlink:title="SoldByRSLMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="SoldByRSLMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to SoldByRSLMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SoldBySellingShareholdersMember" xlink:label="SoldBySellingShareholdersMember" xlink:title="SoldBySellingShareholdersMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="SoldBySellingShareholdersMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to SoldBySellingShareholdersMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RoivantParticipationOfImmunovantStockOfferingMember" xlink:label="RoivantParticipationOfImmunovantStockOfferingMember" xlink:title="RoivantParticipationOfImmunovantStockOfferingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="RoivantParticipationOfImmunovantStockOfferingMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to RoivantParticipationOfImmunovantStockOfferingMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PrivatePlacementMember" xlink:label="PrivatePlacementMember" xlink:title="PrivatePlacementMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="PrivatePlacementMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to PrivatePlacementMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: ScheduleOfStockByClassTable to StatementEquityComponentsAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="CommonStockMember" xlink:title="definition: EquityComponentDomain to CommonStockMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualAxis" xlink:label="TitleOfIndividualAxis" xlink:title="TitleOfIndividualAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="TitleOfIndividualAxis" xlink:title="definition: ScheduleOfStockByClassTable to TitleOfIndividualAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestorMember" xlink:label="InvestorMember" xlink:title="InvestorMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="InvestorMember" xlink:title="definition: TitleOfIndividualWithRelationshipToEntityDomain to InvestorMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="ConsolidatedEntitiesAxis" xlink:title="ConsolidatedEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="ConsolidatedEntitiesAxis" xlink:title="definition: ScheduleOfStockByClassTable to ConsolidatedEntitiesAxis" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="ConsolidatedEntitiesDomain_2" xlink:title="ConsolidatedEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidatedEntitiesAxis" xlink:to="ConsolidatedEntitiesDomain_2" xlink:title="definition: ConsolidatedEntitiesAxis to ConsolidatedEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ImmunovantIncMember" xlink:label="ImmunovantIncMember" xlink:title="ImmunovantIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidatedEntitiesDomain" xlink:to="ImmunovantIncMember" xlink:title="definition: ConsolidatedEntitiesDomain to ImmunovantIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensationStockOptionsAndPerformanceStockOptionsUnderRslEquityPlansDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationAbstract" xlink:label="ShareBasedCompensationAbstract" xlink:title="ShareBasedCompensationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_AggregateIntrinsicValueAbstract" xlink:label="AggregateIntrinsicValueAbstract" xlink:title="AggregateIntrinsicValueAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="AggregateIntrinsicValueAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to AggregateIntrinsicValueAbstract" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to StockIssuedDuringPeriodSharesStockOptionsExercised" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NumberOfEquityIncentivePlans" xlink:label="NumberOfEquityIncentivePlans" xlink:title="NumberOfEquityIncentivePlans" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="NumberOfEquityIncentivePlans" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to NumberOfEquityIncentivePlans" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:label="CommonStockCapitalSharesReservedForFutureIssuance" xlink:title="CommonStockCapitalSharesReservedForFutureIssuance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="CommonStockCapitalSharesReservedForFutureIssuance" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to CommonStockCapitalSharesReservedForFutureIssuance" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EquityIncentivePlanTerm" xlink:label="EquityIncentivePlanTerm" xlink:title="EquityIncentivePlanTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EquityIncentivePlanTerm" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EquityIncentivePlanTerm" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="26.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockOptionsAndPerformanceStockOptionsMember" xlink:label="StockOptionsAndPerformanceStockOptionsMember" xlink:title="StockOptionsAndPerformanceStockOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="StockOptionsAndPerformanceStockOptionsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to StockOptionsAndPerformanceStockOptionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis" xlink:label="PlanNameAxis" xlink:title="PlanNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="PlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to PlanNameAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain" xlink:title="definition: PlanNameAxis to PlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain_2" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain_2" xlink:title="definition: PlanNameAxis to PlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RoivantSciencesLtd2021EquityIncentivePlanMember" xlink:label="RoivantSciencesLtd2021EquityIncentivePlanMember" xlink:title="RoivantSciencesLtd2021EquityIncentivePlanMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="RoivantSciencesLtd2021EquityIncentivePlanMember" xlink:title="definition: PlanNameDomain to RoivantSciencesLtd2021EquityIncentivePlanMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RoivantSciencesLtdEquityPlansMember" xlink:label="RoivantSciencesLtdEquityPlansMember" xlink:title="RoivantSciencesLtdEquityPlansMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="RoivantSciencesLtdEquityPlansMember" xlink:title="definition: PlanNameDomain to RoivantSciencesLtdEquityPlansMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensationBlackscholesClosedFormOptionPricingModelDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationAbstract" xlink:label="ShareBasedCompensationAbstract" xlink:title="ShareBasedCompensationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PerformanceStockUnitsMember" xlink:label="PerformanceStockUnitsMember" xlink:title="PerformanceStockUnitsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="PerformanceStockUnitsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to PerformanceStockUnitsMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensationStockOptionsAndPerformanceStockOptionsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationAbstract" xlink:label="ShareBasedCompensationAbstract" xlink:title="ShareBasedCompensationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IntrinsicValueOfOptionsExercised" xlink:label="IntrinsicValueOfOptionsExercised" xlink:title="IntrinsicValueOfOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="IntrinsicValueOfOptionsExercised" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to IntrinsicValueOfOptionsExercised" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantedWeightedAverageGrantDateFairValue" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantedWeightedAverageGrantDateFairValue" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantedWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantedWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantedWeightedAverageGrantDateFairValue" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockOptionsAndPerformanceStockOptionsMember" xlink:label="StockOptionsAndPerformanceStockOptionsMember" xlink:title="StockOptionsAndPerformanceStockOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="StockOptionsAndPerformanceStockOptionsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to StockOptionsAndPerformanceStockOptionsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensationRestrictedStockUnitsAndPerformanceStockUnitsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="14.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RestrictedStockAndPerformanceStockUnitsMember" xlink:label="RestrictedStockAndPerformanceStockUnitsMember" xlink:title="RestrictedStockAndPerformanceStockUnitsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="RestrictedStockAndPerformanceStockUnitsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to RestrictedStockAndPerformanceStockUnitsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis" xlink:label="PlanNameAxis" xlink:title="PlanNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="PlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to PlanNameAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain" xlink:title="definition: PlanNameAxis to PlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain_2" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain_2" xlink:title="definition: PlanNameAxis to PlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RoivantSciencesLtdEquityPlansMember" xlink:label="RoivantSciencesLtdEquityPlansMember" xlink:title="RoivantSciencesLtdEquityPlansMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="RoivantSciencesLtdEquityPlansMember" xlink:title="definition: PlanNameDomain to RoivantSciencesLtdEquityPlansMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensationCvarsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationAbstract" xlink:label="ShareBasedCompensationAbstract" xlink:title="ShareBasedCompensationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsServiceVestedOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsServiceVestedOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsServiceVestedOutstandingNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsServiceVestedOutstandingNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsServiceVestedOutstandingNumber" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EquityInstrumentsVestedAndSettledShares" xlink:label="EquityInstrumentsVestedAndSettledShares" xlink:title="EquityInstrumentsVestedAndSettledShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EquityInstrumentsVestedAndSettledShares" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EquityInstrumentsVestedAndSettledShares" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ShareBasedPaymentArrangementAwardModificationExpense" xlink:label="ShareBasedPaymentArrangementAwardModificationExpense" xlink:title="ShareBasedPaymentArrangementAwardModificationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedPaymentArrangementAwardModificationExpense" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedPaymentArrangementAwardModificationExpense" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="19.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CappedValueAppreciationRightsMember" xlink:label="CappedValueAppreciationRightsMember" xlink:title="CappedValueAppreciationRightsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="CappedValueAppreciationRightsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to CappedValueAppreciationRightsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis" xlink:label="PlanNameAxis" xlink:title="PlanNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="PlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to PlanNameAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain" xlink:title="definition: PlanNameAxis to PlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain_2" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain_2" xlink:title="definition: PlanNameAxis to PlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_Two015StockBasedIncentiveCompensationPlanMember" xlink:label="Two015StockBasedIncentiveCompensationPlanMember" xlink:title="Two015StockBasedIncentiveCompensationPlanMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="Two015StockBasedIncentiveCompensationPlanMember" xlink:title="definition: PlanNameDomain to Two015StockBasedIncentiveCompensationPlanMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RoivantSciencesLtd2021EquityIncentivePlanMember" xlink:label="RoivantSciencesLtd2021EquityIncentivePlanMember" xlink:title="RoivantSciencesLtd2021EquityIncentivePlanMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="RoivantSciencesLtd2021EquityIncentivePlanMember" xlink:title="definition: PlanNameDomain to RoivantSciencesLtd2021EquityIncentivePlanMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateAxis" xlink:label="AwardDateAxis" xlink:title="AwardDateAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardDateAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardDateAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateDomain" xlink:label="AwardDateDomain" xlink:title="AwardDateDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardDateAxis" xlink:to="AwardDateDomain" xlink:title="definition: AwardDateAxis to AwardDateDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateDomain" xlink:label="AwardDateDomain_2" xlink:title="AwardDateDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardDateAxis" xlink:to="AwardDateDomain_2" xlink:title="definition: AwardDateAxis to AwardDateDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_March2020CappedValueAppreciationRightsGrantsMember" xlink:label="March2020CappedValueAppreciationRightsGrantsMember" xlink:title="March2020CappedValueAppreciationRightsGrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AwardDateDomain" xlink:to="March2020CappedValueAppreciationRightsGrantsMember" xlink:title="definition: AwardDateDomain to March2020CappedValueAppreciationRightsGrantsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_November2021CappedValueAppreciationRightsGrantsMember" xlink:label="November2021CappedValueAppreciationRightsGrantsMember" xlink:title="November2021CappedValueAppreciationRightsGrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AwardDateDomain" xlink:to="November2021CappedValueAppreciationRightsGrantsMember" xlink:title="definition: AwardDateDomain to November2021CappedValueAppreciationRightsGrantsMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensationEmployeeStockPurchasePlanDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EmployeeStockPurchasePlanAbstract" xlink:label="EmployeeStockPurchasePlanAbstract" xlink:title="EmployeeStockPurchasePlanAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeStockPurchasePlanAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeStockPurchasePlanAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PercentageOfStockPurchasePriceEqualToLowerOfClosingPrice" xlink:label="PercentageOfStockPurchasePriceEqualToLowerOfClosingPrice" xlink:title="PercentageOfStockPurchasePriceEqualToLowerOfClosingPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="PercentageOfStockPurchasePriceEqualToLowerOfClosingPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to PercentageOfStockPurchasePriceEqualToLowerOfClosingPrice" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PercentageOfMaximumContributionOfBaseSalary" xlink:label="PercentageOfMaximumContributionOfBaseSalary" xlink:title="PercentageOfMaximumContributionOfBaseSalary" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="PercentageOfMaximumContributionOfBaseSalary" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to PercentageOfMaximumContributionOfBaseSalary" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MaximumAmountOfAnnualContribution" xlink:label="MaximumAmountOfAnnualContribution" xlink:title="MaximumAmountOfAnnualContribution" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="MaximumAmountOfAnnualContribution" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to MaximumAmountOfAnnualContribution" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:title="StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="AllocatedShareBasedCompensationExpense" xlink:title="AllocatedShareBasedCompensationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="AllocatedShareBasedCompensationExpense" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to AllocatedShareBasedCompensationExpense" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="SubsidiarySaleOfStockAxis" xlink:title="SubsidiarySaleOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="SubsidiarySaleOfStockAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to SubsidiarySaleOfStockAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="SaleOfStockNameOfTransactionDomain" xlink:title="SaleOfStockNameOfTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SubsidiarySaleOfStockAxis" xlink:to="SaleOfStockNameOfTransactionDomain" xlink:title="definition: SubsidiarySaleOfStockAxis to SaleOfStockNameOfTransactionDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="SaleOfStockNameOfTransactionDomain_2" xlink:title="SaleOfStockNameOfTransactionDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SubsidiarySaleOfStockAxis" xlink:to="SaleOfStockNameOfTransactionDomain_2" xlink:title="definition: SubsidiarySaleOfStockAxis to SaleOfStockNameOfTransactionDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockMember" xlink:label="EmployeeStockMember" xlink:title="EmployeeStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockNameOfTransactionDomain" xlink:to="EmployeeStockMember" xlink:title="definition: SaleOfStockNameOfTransactionDomain to EmployeeStockMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SharebasedCompensationSubsidiaryEquityIncentivePlansDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SubsidiaryEquityIncentivePlansAbstract" xlink:label="SubsidiaryEquityIncentivePlansAbstract" xlink:title="SubsidiaryEquityIncentivePlansAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SubsidiaryEquityIncentivePlansAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SubsidiaryEquityIncentivePlansAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="AllocatedShareBasedCompensationExpense" xlink:title="AllocatedShareBasedCompensationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="AllocatedShareBasedCompensationExpense" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to AllocatedShareBasedCompensationExpense" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis" xlink:label="PlanNameAxis" xlink:title="PlanNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="PlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to PlanNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain" xlink:title="definition: PlanNameAxis to PlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain_2" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain_2" xlink:title="definition: PlanNameAxis to PlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SubsidiaryEquityIncentivePlansMember" xlink:label="SubsidiaryEquityIncentivePlansMember" xlink:title="SubsidiaryEquityIncentivePlansMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="SubsidiaryEquityIncentivePlansMember" xlink:title="definition: PlanNameDomain to SubsidiaryEquityIncentivePlansMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IncomeTaxesIncomeLossBeforeIncomeTaxesAndRelatedExpenseBenefitDetails">
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IncomeTaxesLineItems" xlink:label="IncomeTaxesLineItems" xlink:title="IncomeTaxesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterestAbstract" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterestAbstract" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterestAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterestAbstract" xlink:title="definition: IncomeTaxesLineItems to IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterestAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="definition: IncomeTaxesLineItems to IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IncomeTaxesTable" xlink:label="IncomeTaxesTable" xlink:title="IncomeTaxesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxesTable" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxesTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeTaxesTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: IncomeTaxesTable to StatementGeographicalAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_BM" xlink:label="BM" xlink:title="BM" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="BM" xlink:title="definition: SegmentGeographicalDomain to BM" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_US" xlink:label="US" xlink:title="US" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="US" xlink:title="definition: SegmentGeographicalDomain to US" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_CH" xlink:label="CH" xlink:title="CH" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="CH" xlink:title="definition: SegmentGeographicalDomain to CH" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OtherMember" xlink:label="OtherMember" xlink:title="OtherMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="OtherMember" xlink:title="definition: SegmentGeographicalDomain to OtherMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IncomeTaxesIncomeTaxExpenseDetails">
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IncomeTaxesLineItems" xlink:label="IncomeTaxesLineItems" xlink:title="IncomeTaxesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="IncomeTaxExpenseBenefitContinuingOperationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxExpenseBenefitContinuingOperationsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="definition: IncomeTaxesLineItems to CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:title="definition: IncomeTaxesLineItems to DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="IncomeTaxExpenseBenefit" xlink:title="IncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxExpenseBenefit" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="DeferredIncomeTaxExpenseBenefit" xlink:title="DeferredIncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredIncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to DeferredIncomeTaxExpenseBenefit" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:label="CurrentIncomeTaxExpenseBenefit" xlink:title="CurrentIncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="CurrentIncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxesLineItems to CurrentIncomeTaxExpenseBenefit" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IncomeTaxesTable" xlink:label="IncomeTaxesTable" xlink:title="IncomeTaxesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxesTable" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxesTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeTaxesTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: IncomeTaxesTable to StatementGeographicalAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_BM" xlink:label="BM" xlink:title="BM" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="BM" xlink:title="definition: SegmentGeographicalDomain to BM" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_US" xlink:label="US" xlink:title="US" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="US" xlink:title="definition: SegmentGeographicalDomain to US" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_CH" xlink:label="CH" xlink:title="CH" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="CH" xlink:title="definition: SegmentGeographicalDomain to CH" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OtherMember" xlink:label="OtherMember" xlink:title="OtherMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="OtherMember" xlink:title="definition: SegmentGeographicalDomain to OtherMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseBenefitDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IncomeTaxesDeferredTaxAssetsLiabilitiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/IncomeTaxesSummaryDetails">
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IncomeTaxesLineItems" xlink:label="IncomeTaxesLineItems" xlink:title="IncomeTaxesLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IncomeTaxOperatingLossesAbstract" xlink:label="IncomeTaxOperatingLossesAbstract" xlink:title="IncomeTaxOperatingLossesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxOperatingLossesAbstract" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxOperatingLossesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="OperatingLossCarryforwards" xlink:title="OperatingLossCarryforwards" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="OperatingLossCarryforwards" xlink:title="definition: IncomeTaxesLineItems to OperatingLossCarryforwards" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLossCarryforwardsExpirationDate" xlink:label="OperatingLossCarryforwardsExpirationDate" xlink:title="OperatingLossCarryforwardsExpirationDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="OperatingLossCarryforwardsExpirationDate" xlink:title="definition: IncomeTaxesLineItems to OperatingLossCarryforwardsExpirationDate" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_AnnualNetOperatingLossUtilizationLimitationPercentage" xlink:label="AnnualNetOperatingLossUtilizationLimitationPercentage" xlink:title="AnnualNetOperatingLossUtilizationLimitationPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="AnnualNetOperatingLossUtilizationLimitationPercentage" xlink:title="definition: IncomeTaxesLineItems to AnnualNetOperatingLossUtilizationLimitationPercentage" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TaxCreditCarryforwardAmount" xlink:label="TaxCreditCarryforwardAmount" xlink:title="TaxCreditCarryforwardAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="TaxCreditCarryforwardAmount" xlink:title="definition: IncomeTaxesLineItems to TaxCreditCarryforwardAmount" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TaxCreditCarryforwardExpirationDate" xlink:label="TaxCreditCarryforwardExpirationDate" xlink:title="TaxCreditCarryforwardExpirationDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="TaxCreditCarryforwardExpirationDate" xlink:title="definition: IncomeTaxesLineItems to TaxCreditCarryforwardExpirationDate" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="DeferredTaxAssetsValuationAllowance" xlink:title="DeferredTaxAssetsValuationAllowance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="DeferredTaxAssetsValuationAllowance" xlink:title="definition: IncomeTaxesLineItems to DeferredTaxAssetsValuationAllowance" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:title="ValuationAllowanceDeferredTaxAssetChangeInAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:title="definition: IncomeTaxesLineItems to ValuationAllowanceDeferredTaxAssetChangeInAmount" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:label="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:title="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxesLineItems" xlink:to="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:title="definition: IncomeTaxesLineItems to UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IncomeTaxesTable" xlink:label="IncomeTaxesTable" xlink:title="IncomeTaxesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IncomeTaxesLineItems" xlink:to="IncomeTaxesTable" xlink:title="definition: IncomeTaxesLineItems to IncomeTaxesTable" order="10.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeTaxesTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: IncomeTaxesTable to StatementGeographicalAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_CH" xlink:label="CH" xlink:title="CH" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="CH" xlink:title="definition: SegmentGeographicalDomain to CH" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_US" xlink:label="US" xlink:title="US" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="US" xlink:title="definition: SegmentGeographicalDomain to US" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_GB" xlink:label="GB" xlink:title="GB" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="GB" xlink:title="definition: SegmentGeographicalDomain to GB" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_UnitedStatesAndCanadaMember" xlink:label="UnitedStatesAndCanadaMember" xlink:title="UnitedStatesAndCanadaMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="UnitedStatesAndCanadaMember" xlink:title="definition: SegmentGeographicalDomain to UnitedStatesAndCanadaMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeTaxesTable" xlink:to="RangeAxis" xlink:title="definition: IncomeTaxesTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LeasesComponentsOfOperatingLeaseExpenseDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LeasesOperatingLeaseRightofuseAssetsAndLeaseLiabilitiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/LeasesMaturitiesOfOperatingLeaseLiabilitiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/CommitmentsAndContingenciesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermPurchaseCommitmentLineItems" xlink:label="LongTermPurchaseCommitmentLineItems" xlink:title="LongTermPurchaseCommitmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract" xlink:label="LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract" xlink:title="LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract" xlink:title="definition: LongTermPurchaseCommitmentLineItems to LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MaximumPotentialFutureMilestonePayments" xlink:label="MaximumPotentialFutureMilestonePayments" xlink:title="MaximumPotentialFutureMilestonePayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="MaximumPotentialFutureMilestonePayments" xlink:title="definition: LongTermPurchaseCommitmentLineItems to MaximumPotentialFutureMilestonePayments" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FirstMilestonePayableAmountUnderRemainingCommercialMilestones" xlink:label="FirstMilestonePayableAmountUnderRemainingCommercialMilestones" xlink:title="FirstMilestonePayableAmountUnderRemainingCommercialMilestones" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="FirstMilestonePayableAmountUnderRemainingCommercialMilestones" xlink:title="definition: LongTermPurchaseCommitmentLineItems to FirstMilestonePayableAmountUnderRemainingCommercialMilestones" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermPurchaseCommitmentPeriod" xlink:label="LongtermPurchaseCommitmentPeriod" xlink:title="LongtermPurchaseCommitmentPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="LongtermPurchaseCommitmentPeriod" xlink:title="definition: LongTermPurchaseCommitmentLineItems to LongtermPurchaseCommitmentPeriod" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PeriodOfRightToTerminateTheProductServiceAgreement" xlink:label="PeriodOfRightToTerminateTheProductServiceAgreement" xlink:title="PeriodOfRightToTerminateTheProductServiceAgreement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="PeriodOfRightToTerminateTheProductServiceAgreement" xlink:title="definition: LongTermPurchaseCommitmentLineItems to PeriodOfRightToTerminateTheProductServiceAgreement" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PeriodToPurchaseAdditionalBatchesOfBatoclimab" xlink:label="PeriodToPurchaseAdditionalBatchesOfBatoclimab" xlink:title="PeriodToPurchaseAdditionalBatchesOfBatoclimab" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="PeriodToPurchaseAdditionalBatchesOfBatoclimab" xlink:title="definition: LongTermPurchaseCommitmentLineItems to PeriodToPurchaseAdditionalBatchesOfBatoclimab" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RemainingMinimumPurchaseCommitmentRelatedToAgreement" xlink:label="RemainingMinimumPurchaseCommitmentRelatedToAgreement" xlink:title="RemainingMinimumPurchaseCommitmentRelatedToAgreement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="RemainingMinimumPurchaseCommitmentRelatedToAgreement" xlink:title="definition: LongTermPurchaseCommitmentLineItems to RemainingMinimumPurchaseCommitmentRelatedToAgreement" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="EmployeeRelatedLiabilitiesCurrent" xlink:title="EmployeeRelatedLiabilitiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="EmployeeRelatedLiabilitiesCurrent" xlink:title="definition: LongTermPurchaseCommitmentLineItems to EmployeeRelatedLiabilitiesCurrent" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="SellingGeneralAndAdministrativeExpense" xlink:title="SellingGeneralAndAdministrativeExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="SellingGeneralAndAdministrativeExpense" xlink:title="definition: LongTermPurchaseCommitmentLineItems to SellingGeneralAndAdministrativeExpense" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="ResearchAndDevelopmentExpense" xlink:title="ResearchAndDevelopmentExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="ResearchAndDevelopmentExpense" xlink:title="definition: LongTermPurchaseCommitmentLineItems to ResearchAndDevelopmentExpense" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RemainingEmployeeRelatedLiabilitiesCurrent" xlink:label="RemainingEmployeeRelatedLiabilitiesCurrent" xlink:title="RemainingEmployeeRelatedLiabilitiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="RemainingEmployeeRelatedLiabilitiesCurrent" xlink:title="definition: LongTermPurchaseCommitmentLineItems to RemainingEmployeeRelatedLiabilitiesCurrent" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermPurchaseCommitmentTable" xlink:label="LongTermPurchaseCommitmentTable" xlink:title="LongTermPurchaseCommitmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="LongTermPurchaseCommitmentLineItems" xlink:to="LongTermPurchaseCommitmentTable" xlink:title="definition: LongTermPurchaseCommitmentLineItems to LongTermPurchaseCommitmentTable" order="12.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="TypeOfArrangementAxis" xlink:title="TypeOfArrangementAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LongTermPurchaseCommitmentTable" xlink:to="TypeOfArrangementAxis" xlink:title="definition: LongTermPurchaseCommitmentTable to TypeOfArrangementAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SamsungBiologicsCo.Ltd.Member" xlink:label="SamsungBiologicsCo.Ltd.Member" xlink:title="SamsungBiologicsCo.Ltd.Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="SamsungBiologicsCo.Ltd.Member" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to SamsungBiologicsCo.Ltd.Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CashBonusProgramMember" xlink:label="CashBonusProgramMember" xlink:title="CashBonusProgramMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="CashBonusProgramMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to CashBonusProgramMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LongTermPurchaseCommitmentTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: LongTermPurchaseCommitmentTable to BusinessAcquisitionAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DermavantMember" xlink:label="DermavantMember" xlink:title="DermavantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DermavantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DermavantMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_HanAllBiopharmaCoLtdImmunovantMember" xlink:label="HanAllBiopharmaCoLtdImmunovantMember" xlink:title="HanAllBiopharmaCoLtdImmunovantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="HanAllBiopharmaCoLtdImmunovantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to HanAllBiopharmaCoLtdImmunovantMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PriovantTherapeuticsIncMember" xlink:label="PriovantTherapeuticsIncMember" xlink:title="PriovantTherapeuticsIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="PriovantTherapeuticsIncMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to PriovantTherapeuticsIncMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_IzanaBiosciencesLimitedKinevantLtdMember" xlink:label="IzanaBiosciencesLimitedKinevantLtdMember" xlink:title="IzanaBiosciencesLimitedKinevantLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="IzanaBiosciencesLimitedKinevantLtdMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to IzanaBiosciencesLimitedKinevantLtdMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" xlink:label="LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" xlink:title="LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LongTermPurchaseCommitmentTable" xlink:to="LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" xlink:title="definition: LongTermPurchaseCommitmentTable to LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:label="LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:title="LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" xlink:to="LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:title="definition: LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis to LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:label="LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_2" xlink:title="LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" xlink:to="LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_2" xlink:title="definition: LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis to LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GSKMember" xlink:label="GSKMember" xlink:title="GSKMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:to="GSKMember" xlink:title="definition: LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain to GSKMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualAxis" xlink:label="TitleOfIndividualAxis" xlink:title="TitleOfIndividualAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LongTermPurchaseCommitmentTable" xlink:to="TitleOfIndividualAxis" xlink:title="definition: LongTermPurchaseCommitmentTable to TitleOfIndividualAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ChiefFinancialOfficerMember" xlink:label="ChiefFinancialOfficerMember" xlink:title="ChiefFinancialOfficerMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="ChiefFinancialOfficerMember" xlink:title="definition: TitleOfIndividualWithRelationshipToEntityDomain to ChiefFinancialOfficerMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/EarnoutSharesPublicWarrantsAndPrivatePlacementWarrantsDetails">
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:label="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:title="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnOutSharesAbstract" xlink:label="EarnOutSharesAbstract" xlink:title="EarnOutSharesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="EarnOutSharesAbstract" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to EarnOutSharesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PublicWarrantsAndPrivatePlacementWarrantsAbstract" xlink:label="PublicWarrantsAndPrivatePlacementWarrantsAbstract" xlink:title="PublicWarrantsAndPrivatePlacementWarrantsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="PublicWarrantsAndPrivatePlacementWarrantsAbstract" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to PublicWarrantsAndPrivatePlacementWarrantsAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightOutstanding" xlink:label="ClassOfWarrantOrRightOutstanding" xlink:title="ClassOfWarrantOrRightOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="ClassOfWarrantOrRightOutstanding" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to ClassOfWarrantOrRightOutstanding" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:title="ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PeriodToExerciseWarrantsAfterBusinessCombination" xlink:label="PeriodToExerciseWarrantsAfterBusinessCombination" xlink:title="PeriodToExerciseWarrantsAfterBusinessCombination" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="PeriodToExerciseWarrantsAfterBusinessCombination" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to PeriodToExerciseWarrantsAfterBusinessCombination" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantsAndRightsOutstandingTerm" xlink:label="WarrantsAndRightsOutstandingTerm" xlink:title="WarrantsAndRightsOutstandingTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="WarrantsAndRightsOutstandingTerm" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to WarrantsAndRightsOutstandingTerm" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ClassOfWarrantOrRightRedemptionPrice" xlink:label="ClassOfWarrantOrRightRedemptionPrice" xlink:title="ClassOfWarrantOrRightRedemptionPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="ClassOfWarrantOrRightRedemptionPrice" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to ClassOfWarrantOrRightRedemptionPrice" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockPricePerShare" xlink:label="SaleOfStockPricePerShare" xlink:title="SaleOfStockPricePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="SaleOfStockPricePerShare" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to SaleOfStockPricePerShare" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NumberOfTradingDays" xlink:label="NumberOfTradingDays" xlink:title="NumberOfTradingDays" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="NumberOfTradingDays" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to NumberOfTradingDays" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CashExercisePrice" xlink:label="CashExercisePrice" xlink:title="CashExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="CashExercisePrice" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to CashExercisePrice" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ExercisePrice" xlink:label="ExercisePrice" xlink:title="ExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="ExercisePrice" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to ExercisePrice" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodNumberOfSharesIssuedToSurrenderingHolderPerWarrant" xlink:label="StockIssuedDuringPeriodNumberOfSharesIssuedToSurrenderingHolderPerWarrant" xlink:title="StockIssuedDuringPeriodNumberOfSharesIssuedToSurrenderingHolderPerWarrant" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="StockIssuedDuringPeriodNumberOfSharesIssuedToSurrenderingHolderPerWarrant" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to StockIssuedDuringPeriodNumberOfSharesIssuedToSurrenderingHolderPerWarrant" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PublicWarrantCashExercised" xlink:label="PublicWarrantCashExercised" xlink:title="PublicWarrantCashExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="PublicWarrantCashExercised" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to PublicWarrantCashExercised" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CashlessPublicWarrantExercised" xlink:label="CashlessPublicWarrantExercised" xlink:title="CashlessPublicWarrantExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="CashlessPublicWarrantExercised" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to CashlessPublicWarrantExercised" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodSharesCashWarrantExercises" xlink:label="StockIssuedDuringPeriodSharesCashWarrantExercises" xlink:title="StockIssuedDuringPeriodSharesCashWarrantExercises" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="StockIssuedDuringPeriodSharesCashWarrantExercises" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to StockIssuedDuringPeriodSharesCashWarrantExercises" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockIssuedDuringPeriodSharesCashlessWarrantExercises" xlink:label="StockIssuedDuringPeriodSharesCashlessWarrantExercises" xlink:title="StockIssuedDuringPeriodSharesCashlessWarrantExercises" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="StockIssuedDuringPeriodSharesCashlessWarrantExercises" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to StockIssuedDuringPeriodSharesCashlessWarrantExercises" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ClassOfWarrantOrRightUnexercisedPriceOfWarrants" xlink:label="ClassOfWarrantOrRightUnexercisedPriceOfWarrants" xlink:title="ClassOfWarrantOrRightUnexercisedPriceOfWarrants" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="ClassOfWarrantOrRightUnexercisedPriceOfWarrants" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to ClassOfWarrantOrRightUnexercisedPriceOfWarrants" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="StockIssuedDuringPeriodSharesNewIssues" xlink:title="StockIssuedDuringPeriodSharesNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="StockIssuedDuringPeriodSharesNewIssues" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to StockIssuedDuringPeriodSharesNewIssues" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PercentageOfEarnOutShares" xlink:label="PercentageOfEarnOutShares" xlink:title="PercentageOfEarnOutShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="PercentageOfEarnOutShares" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to PercentageOfEarnOutShares" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnOutSharePrice" xlink:label="EarnOutSharePrice" xlink:title="EarnOutSharePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="EarnOutSharePrice" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to EarnOutSharePrice" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NumberOfTradingDaysToBeUsedToMeetEarnOutSharePriceThreshold" xlink:label="NumberOfTradingDaysToBeUsedToMeetEarnOutSharePriceThreshold" xlink:title="NumberOfTradingDaysToBeUsedToMeetEarnOutSharePriceThreshold" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="NumberOfTradingDaysToBeUsedToMeetEarnOutSharePriceThreshold" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to NumberOfTradingDaysToBeUsedToMeetEarnOutSharePriceThreshold" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NumberOfTradingDaysAllowedToCalculateEarnOutSharePriceThreshold" xlink:label="NumberOfTradingDaysAllowedToCalculateEarnOutSharePriceThreshold" xlink:title="NumberOfTradingDaysAllowedToCalculateEarnOutSharePriceThreshold" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="NumberOfTradingDaysAllowedToCalculateEarnOutSharePriceThreshold" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to NumberOfTradingDaysAllowedToCalculateEarnOutSharePriceThreshold" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NumberOfEarnOutSharesVested" xlink:label="NumberOfEarnOutSharesVested" xlink:title="NumberOfEarnOutSharesVested" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="NumberOfEarnOutSharesVested" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to NumberOfEarnOutSharesVested" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:label="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:title="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems" xlink:to="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsLineItems to EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" order="24.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable to RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PatientSquareCapitalLimitedLiabilityCompanyMember" xlink:label="PatientSquareCapitalLimitedLiabilityCompanyMember" xlink:title="PatientSquareCapitalLimitedLiabilityCompanyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="PatientSquareCapitalLimitedLiabilityCompanyMember" xlink:title="definition: RelatedPartyDomain to PatientSquareCapitalLimitedLiabilityCompanyMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="ClassOfWarrantOrRightAxis" xlink:title="ClassOfWarrantOrRightAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:to="ClassOfWarrantOrRightAxis" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable to ClassOfWarrantOrRightAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain_2" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain_2" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PrivatePlacementWarrantsMember" xlink:label="PrivatePlacementWarrantsMember" xlink:title="PrivatePlacementWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="PrivatePlacementWarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to PrivatePlacementWarrantsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PublicWarrantsMember" xlink:label="PublicWarrantsMember" xlink:title="PublicWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="PublicWarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to PublicWarrantsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PublicWarrantsAndPrivatePlacementWarrantsMember" xlink:label="PublicWarrantsAndPrivatePlacementWarrantsMember" xlink:title="PublicWarrantsAndPrivatePlacementWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="PublicWarrantsAndPrivatePlacementWarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to PublicWarrantsAndPrivatePlacementWarrantsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualAxis" xlink:label="TitleOfIndividualAxis" xlink:title="TitleOfIndividualAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:to="TitleOfIndividualAxis" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable to TitleOfIndividualAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_DirectorMember" xlink:label="DirectorMember" xlink:title="DirectorMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="DirectorMember" xlink:title="definition: TitleOfIndividualWithRelationshipToEntityDomain to DirectorMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable to StatementEquityComponentsAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_TwentyPercentEarnOutSharesMember" xlink:label="TwentyPercentEarnOutSharesMember" xlink:title="TwentyPercentEarnOutSharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="TwentyPercentEarnOutSharesMember" xlink:title="definition: EquityComponentDomain to TwentyPercentEarnOutSharesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_TenPercentEarnOutSharesMember" xlink:label="TenPercentEarnOutSharesMember" xlink:title="TenPercentEarnOutSharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="TenPercentEarnOutSharesMember" xlink:title="definition: EquityComponentDomain to TenPercentEarnOutSharesMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable to StatementClassOfStockAxis" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonStockMember" xlink:title="definition: ClassOfStockDomain to CommonStockMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable" xlink:to="RangeAxis" xlink:title="definition: EarnOutSharesPublicWarrantsAndPrivatePlacementWarrantsTable to RangeAxis" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/FairValueMeasurementsAssetsAndLiabilitiesAreMeasuredAtFairValueOnRecurringBasisDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="AssetsFairValueDisclosureAbstract" xlink:title="AssetsFairValueDisclosureAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="AssetsFairValueDisclosureAbstract" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to AssetsFairValueDisclosureAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="LiabilitiesFairValueDisclosureAbstract" xlink:title="LiabilitiesFairValueDisclosureAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="LiabilitiesFairValueDisclosureAbstract" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to LiabilitiesFairValueDisclosureAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialLiabilitiesFairValueDisclosure" xlink:label="FinancialLiabilitiesFairValueDisclosure" xlink:title="FinancialLiabilitiesFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FinancialLiabilitiesFairValueDisclosure" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FinancialLiabilitiesFairValueDisclosure" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="LiabilitiesFairValueDisclosure" xlink:title="LiabilitiesFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="LiabilitiesFairValueDisclosure" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to LiabilitiesFairValueDisclosure" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OtherLiabilityInstrumentsMeasuredAtFairValueMeasurement" xlink:label="OtherLiabilityInstrumentsMeasuredAtFairValueMeasurement" xlink:title="OtherLiabilityInstrumentsMeasuredAtFairValueMeasurement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="OtherLiabilityInstrumentsMeasuredAtFairValueMeasurement" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to OtherLiabilityInstrumentsMeasuredAtFairValueMeasurement" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFairValue" xlink:label="DebtInstrumentFairValue" xlink:title="DebtInstrumentFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="DebtInstrumentFairValue" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to DebtInstrumentFairValue" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" xlink:label="DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" xlink:title="DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeLiabilities" xlink:label="DerivativeLiabilities" xlink:title="DerivativeLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="DerivativeLiabilities" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to DerivativeLiabilities" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="CashAndCashEquivalentsFairValueDisclosure" xlink:title="CashAndCashEquivalentsFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="CashAndCashEquivalentsFairValueDisclosure" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to CashAndCashEquivalentsFairValueDisclosure" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestmentsFairValueDisclosure" xlink:label="InvestmentsFairValueDisclosure" xlink:title="InvestmentsFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="InvestmentsFairValueDisclosure" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to InvestmentsFairValueDisclosure" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="AssetsFairValueDisclosure" xlink:title="AssetsFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="AssetsFairValueDisclosure" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to AssetsFairValueDisclosure" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" order="13.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="FairValueByMeasurementFrequencyAxis" xlink:title="FairValueByMeasurementFrequencyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FairValueByMeasurementFrequencyAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FairValueByMeasurementFrequencyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="FairValueMeasurementFrequencyDomain" xlink:title="FairValueMeasurementFrequencyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByMeasurementFrequencyAxis" xlink:to="FairValueMeasurementFrequencyDomain" xlink:title="definition: FairValueByMeasurementFrequencyAxis to FairValueMeasurementFrequencyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="FairValueMeasurementFrequencyDomain_2" xlink:title="FairValueMeasurementFrequencyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByMeasurementFrequencyAxis" xlink:to="FairValueMeasurementFrequencyDomain_2" xlink:title="definition: FairValueByMeasurementFrequencyAxis to FairValueMeasurementFrequencyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="FairValueMeasurementsRecurringMember" xlink:title="FairValueMeasurementsRecurringMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementFrequencyDomain" xlink:to="FairValueMeasurementsRecurringMember" xlink:title="definition: FairValueMeasurementFrequencyDomain to FairValueMeasurementsRecurringMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="FairValueByFairValueHierarchyLevelAxis" xlink:title="FairValueByFairValueHierarchyLevelAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FairValueByFairValueHierarchyLevelAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FairValueByFairValueHierarchyLevelAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="FairValueInputsLevel1Member" xlink:title="FairValueInputsLevel1Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel1Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel1Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="FairValueInputsLevel2Member" xlink:title="FairValueInputsLevel2Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel2Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel2Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="FairValueInputsLevel3Member" xlink:title="FairValueInputsLevel3Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel3Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel3Member" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByAssetClassAxis" xlink:label="FairValueByAssetClassAxis" xlink:title="FairValueByAssetClassAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FairValueByAssetClassAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FairValueByAssetClassAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:label="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:title="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByAssetClassAxis" xlink:to="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:title="definition: FairValueByAssetClassAxis to FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:label="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2" xlink:title="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByAssetClassAxis" xlink:to="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2" xlink:title="definition: FairValueByAssetClassAxis to FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MoneyMarketFundsMember" xlink:label="MoneyMarketFundsMember" xlink:title="MoneyMarketFundsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="MoneyMarketFundsMember" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain to MoneyMarketFundsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="CommonStockMember" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain to CommonStockMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherInvestmentCompaniesMember" xlink:label="OtherInvestmentCompaniesMember" xlink:title="OtherInvestmentCompaniesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="OtherInvestmentCompaniesMember" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain to OtherInvestmentCompaniesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain_2" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain_2" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DatavantHoldingsIncMember" xlink:label="DatavantHoldingsIncMember" xlink:title="DatavantHoldingsIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="DatavantHoldingsIncMember" xlink:title="definition: EquityMethodInvesteeNameDomain to DatavantHoldingsIncMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ArbutusBiopharmaCorporationMember" xlink:label="ArbutusBiopharmaCorporationMember" xlink:title="ArbutusBiopharmaCorporationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="ArbutusBiopharmaCorporationMember" xlink:title="definition: EquityMethodInvesteeNameDomain to ArbutusBiopharmaCorporationMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="FinancialInstrumentAxis" xlink:title="FinancialInstrumentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FinancialInstrumentAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FinancialInstrumentAxis" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:title="TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FinancialInstrumentAxis" xlink:to="TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:title="definition: FinancialInstrumentAxis to TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2" xlink:title="TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FinancialInstrumentAxis" xlink:to="TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2" xlink:title="definition: FinancialInstrumentAxis to TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantMember" xlink:label="WarrantMember" xlink:title="WarrantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="WarrantMember" xlink:title="definition: TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain to WarrantMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_LiabilityInstrumentsMeasuredAtFairValueMember" xlink:label="LiabilityInstrumentsMeasuredAtFairValueMember" xlink:title="LiabilityInstrumentsMeasuredAtFairValueMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="LiabilityInstrumentsMeasuredAtFairValueMember" xlink:title="definition: TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain to LiabilityInstrumentsMeasuredAtFairValueMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="ClassOfWarrantOrRightAxis" xlink:title="ClassOfWarrantOrRightAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="ClassOfWarrantOrRightAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to ClassOfWarrantOrRightAxis" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain_2" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain_2" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RedeemableWarrantsMember" xlink:label="RedeemableWarrantsMember" xlink:title="RedeemableWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="RedeemableWarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to RedeemableWarrantsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PrivatePlacementWarrantsMember" xlink:label="PrivatePlacementWarrantsMember" xlink:title="PrivatePlacementWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="PrivatePlacementWarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to PrivatePlacementWarrantsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to StatementEquityComponentsAxis" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnoutSharesMember" xlink:label="EarnoutSharesMember" xlink:title="EarnoutSharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="EarnoutSharesMember" xlink:title="definition: EquityComponentDomain to EarnoutSharesMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/FairValueMeasurementsChangesInFairValueOfLevel3AssetsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:label="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:title="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:title="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList" xlink:label="FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList" xlink:title="FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:label="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:title="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="FairValueByFairValueHierarchyLevelAxis" xlink:title="FairValueByFairValueHierarchyLevelAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:to="FairValueByFairValueHierarchyLevelAxis" xlink:title="definition: FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable to FairValueByFairValueHierarchyLevelAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="FairValueInputsLevel3Member" xlink:title="FairValueInputsLevel3Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel3Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel3Member" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/FairValueMeasurementsChangesInFairValueOfLevel3LiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:label="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:title="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:title="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="RepaymentsOfLongTermDebt" xlink:title="RepaymentsOfLongTermDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="RepaymentsOfLongTermDebt" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to RepaymentsOfLongTermDebt" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ExerciseOfPrivatePlacementWarrantsValue" xlink:label="ExerciseOfPrivatePlacementWarrantsValue" xlink:title="ExerciseOfPrivatePlacementWarrantsValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="ExerciseOfPrivatePlacementWarrantsValue" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to ExerciseOfPrivatePlacementWarrantsValue" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueRecurringBasisUnobservableInputReconciliationLiabilityGainLossStatementOfIncomeExtensibleList" xlink:label="FairValueRecurringBasisUnobservableInputReconciliationLiabilityGainLossStatementOfIncomeExtensibleList" xlink:title="FairValueRecurringBasisUnobservableInputReconciliationLiabilityGainLossStatementOfIncomeExtensibleList" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueRecurringBasisUnobservableInputReconciliationLiabilityGainLossStatementOfIncomeExtensibleList" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueRecurringBasisUnobservableInputReconciliationLiabilityGainLossStatementOfIncomeExtensibleList" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:label="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:title="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="FairValueByFairValueHierarchyLevelAxis" xlink:title="FairValueByFairValueHierarchyLevelAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:to="FairValueByFairValueHierarchyLevelAxis" xlink:title="definition: FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable to FairValueByFairValueHierarchyLevelAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="FairValueInputsLevel3Member" xlink:title="FairValueInputsLevel3Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel3Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel3Member" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/FairValueMeasurementsFairValueOfSignificantUnobservableInputsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FairValueMeasurementInputsAndValuationTechniquesAbstract" xlink:label="FairValueMeasurementInputsAndValuationTechniquesAbstract" xlink:title="FairValueMeasurementInputsAndValuationTechniquesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="FairValueMeasurementInputsAndValuationTechniquesAbstract" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to FairValueMeasurementInputsAndValuationTechniquesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FairValueAssetMeasurementInput" xlink:label="FairValueAssetMeasurementInput" xlink:title="FairValueAssetMeasurementInput" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="FairValueAssetMeasurementInput" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to FairValueAssetMeasurementInput" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FairValueEarnoutSharesMeasurementInput" xlink:label="FairValueEarnoutSharesMeasurementInput" xlink:title="FairValueEarnoutSharesMeasurementInput" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="FairValueEarnoutSharesMeasurementInput" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to FairValueEarnoutSharesMeasurementInput" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantsAndRightsOutstandingMeasurementInput" xlink:label="WarrantsAndRightsOutstandingMeasurementInput" xlink:title="WarrantsAndRightsOutstandingMeasurementInput" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="WarrantsAndRightsOutstandingMeasurementInput" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to WarrantsAndRightsOutstandingMeasurementInput" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WarrantsAndRightsOutstandingTerm" xlink:label="WarrantsAndRightsOutstandingTerm" xlink:title="WarrantsAndRightsOutstandingTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="WarrantsAndRightsOutstandingTerm" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to WarrantsAndRightsOutstandingTerm" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="LiabilitiesFairValueDisclosure" xlink:title="LiabilitiesFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="LiabilitiesFairValueDisclosure" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to LiabilitiesFairValueDisclosure" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnOutShareRedemptionTriggerPrice" xlink:label="EarnOutShareRedemptionTriggerPrice" xlink:title="EarnOutShareRedemptionTriggerPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="EarnOutShareRedemptionTriggerPrice" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to EarnOutShareRedemptionTriggerPrice" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeLiabilities" xlink:label="DerivativeLiabilities" xlink:title="DerivativeLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="DerivativeLiabilities" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to DerivativeLiabilities" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" xlink:label="DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" xlink:title="DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" order="10.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis" xlink:label="MeasurementInputTypeAxis" xlink:title="MeasurementInputTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="MeasurementInputTypeAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable to MeasurementInputTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain" xlink:label="MeasurementInputTypeDomain" xlink:title="MeasurementInputTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="MeasurementInputTypeAxis" xlink:to="MeasurementInputTypeDomain" xlink:title="definition: MeasurementInputTypeAxis to MeasurementInputTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain" xlink:label="MeasurementInputTypeDomain_2" xlink:title="MeasurementInputTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MeasurementInputTypeAxis" xlink:to="MeasurementInputTypeDomain_2" xlink:title="definition: MeasurementInputTypeAxis to MeasurementInputTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputPriceVolatilityMember" xlink:label="MeasurementInputPriceVolatilityMember" xlink:title="MeasurementInputPriceVolatilityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MeasurementInputTypeDomain" xlink:to="MeasurementInputPriceVolatilityMember" xlink:title="definition: MeasurementInputTypeDomain to MeasurementInputPriceVolatilityMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember" xlink:label="MeasurementInputRiskFreeInterestRateMember" xlink:title="MeasurementInputRiskFreeInterestRateMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MeasurementInputTypeDomain" xlink:to="MeasurementInputRiskFreeInterestRateMember" xlink:title="definition: MeasurementInputTypeDomain to MeasurementInputRiskFreeInterestRateMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputExpectedTermMember" xlink:label="MeasurementInputExpectedTermMember" xlink:title="MeasurementInputExpectedTermMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MeasurementInputTypeDomain" xlink:to="MeasurementInputExpectedTermMember" xlink:title="definition: MeasurementInputTypeDomain to MeasurementInputExpectedTermMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="ClassOfWarrantOrRightAxis" xlink:title="ClassOfWarrantOrRightAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="ClassOfWarrantOrRightAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable to ClassOfWarrantOrRightAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="ClassOfWarrantOrRightDomain_2" xlink:title="ClassOfWarrantOrRightDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassOfWarrantOrRightAxis" xlink:to="ClassOfWarrantOrRightDomain_2" xlink:title="definition: ClassOfWarrantOrRightAxis to ClassOfWarrantOrRightDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PrivatePlacementWarrantsMember" xlink:label="PrivatePlacementWarrantsMember" xlink:title="PrivatePlacementWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfWarrantOrRightDomain" xlink:to="PrivatePlacementWarrantsMember" xlink:title="definition: ClassOfWarrantOrRightDomain to PrivatePlacementWarrantsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable to StatementEquityComponentsAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnoutSharesMember" xlink:label="EarnoutSharesMember" xlink:title="EarnoutSharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="EarnoutSharesMember" xlink:title="definition: EquityComponentDomain to EarnoutSharesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable to ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="EquityMethodInvesteeNameDomain_2" xlink:title="EquityMethodInvesteeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="EquityMethodInvesteeNameDomain_2" xlink:title="definition: ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis to EquityMethodInvesteeNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DatavantHoldingsIncMember" xlink:label="DatavantHoldingsIncMember" xlink:title="DatavantHoldingsIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityMethodInvesteeNameDomain" xlink:to="DatavantHoldingsIncMember" xlink:title="definition: EquityMethodInvesteeNameDomain to DatavantHoldingsIncMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="RangeAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable to RangeAxis" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/NetIncomeLossPerCommonShareDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareDilutedOtherDisclosuresAbstract" xlink:label="EarningsPerShareDilutedOtherDisclosuresAbstract" xlink:title="EarningsPerShareDilutedOtherDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="EarningsPerShareDilutedOtherDisclosuresAbstract" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to EarningsPerShareDilutedOtherDisclosuresAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:title="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:title="definition: ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable to AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="AntidilutiveSecuritiesNameDomain" xlink:title="AntidilutiveSecuritiesNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesNameDomain" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis to AntidilutiveSecuritiesNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="AntidilutiveSecuritiesNameDomain_2" xlink:title="AntidilutiveSecuritiesNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesNameDomain_2" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis to AntidilutiveSecuritiesNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockOptionsAndPerformanceStockOptionsMember" xlink:label="StockOptionsAndPerformanceStockOptionsMember" xlink:title="StockOptionsAndPerformanceStockOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="StockOptionsAndPerformanceStockOptionsMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to StockOptionsAndPerformanceStockOptionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RestrictedStockAndPerformanceStockUnitsMember" xlink:label="RestrictedStockAndPerformanceStockUnitsMember" xlink:title="RestrictedStockAndPerformanceStockUnitsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="RestrictedStockAndPerformanceStockUnitsMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to RestrictedStockAndPerformanceStockUnitsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_March2020CappedValueAppreciationRightsGrantsMember" xlink:label="March2020CappedValueAppreciationRightsGrantsMember" xlink:title="March2020CappedValueAppreciationRightsGrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="March2020CappedValueAppreciationRightsGrantsMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to March2020CappedValueAppreciationRightsGrantsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_November2021CappedValueAppreciationRightsGrantsMember" xlink:label="November2021CappedValueAppreciationRightsGrantsMember" xlink:title="November2021CappedValueAppreciationRightsGrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="November2021CappedValueAppreciationRightsGrantsMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to November2021CappedValueAppreciationRightsGrantsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RestrictedCommonStockMember" xlink:label="RestrictedCommonStockMember" xlink:title="RestrictedCommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="RestrictedCommonStockMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to RestrictedCommonStockMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_EarnOutSharesNonvestedMember" xlink:label="EarnOutSharesNonvestedMember" xlink:title="EarnOutSharesNonvestedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="EarnOutSharesNonvestedMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to EarnOutSharesNonvestedMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PrivatePlacementWarrantsMember" xlink:label="PrivatePlacementWarrantsMember" xlink:title="PrivatePlacementWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="PrivatePlacementWarrantsMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to PrivatePlacementWarrantsMember" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_PublicWarrantsMember" xlink:label="PublicWarrantsMember" xlink:title="PublicWarrantsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="PublicWarrantsMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to PublicWarrantsMember" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OtherStockBasedAwardsAndInstrumentsIssuedMember" xlink:label="OtherStockBasedAwardsAndInstrumentsIssuedMember" xlink:title="OtherStockBasedAwardsAndInstrumentsIssuedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="OtherStockBasedAwardsAndInstrumentsIssuedMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to OtherStockBasedAwardsAndInstrumentsIssuedMember" order="9.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://roivant.com/role/SubsequentEventsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventLineItems" xlink:label="SubsequentEventLineItems" xlink:title="SubsequentEventLineItems" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CommonShareRepurchaseProgramAbstract" xlink:label="CommonShareRepurchaseProgramAbstract" xlink:title="CommonShareRepurchaseProgramAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="CommonShareRepurchaseProgramAbstract" xlink:title="definition: SubsequentEventLineItems to CommonShareRepurchaseProgramAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:label="StockRepurchaseProgramAuthorizedAmount1" xlink:title="StockRepurchaseProgramAuthorizedAmount1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="StockRepurchaseProgramAuthorizedAmount1" xlink:title="definition: SubsequentEventLineItems to StockRepurchaseProgramAuthorizedAmount1" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NumberOfStockRepurchasedDuringPeriodShares" xlink:label="NumberOfStockRepurchasedDuringPeriodShares" xlink:title="NumberOfStockRepurchasedDuringPeriodShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="NumberOfStockRepurchasedDuringPeriodShares" xlink:title="definition: SubsequentEventLineItems to NumberOfStockRepurchasedDuringPeriodShares" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharePrice" xlink:label="SharePrice" xlink:title="SharePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="SharePrice" xlink:title="definition: SubsequentEventLineItems to SharePrice" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_AggregateAmountForStockRepurchasedDuringPeriodValue" xlink:label="AggregateAmountForStockRepurchasedDuringPeriodValue" xlink:title="AggregateAmountForStockRepurchasedDuringPeriodValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="AggregateAmountForStockRepurchasedDuringPeriodValue" xlink:title="definition: SubsequentEventLineItems to AggregateAmountForStockRepurchasedDuringPeriodValue" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_TotalRequiredDebtInstrumentQuarterlyPaymentsMade" xlink:label="TotalRequiredDebtInstrumentQuarterlyPaymentsMade" xlink:title="TotalRequiredDebtInstrumentQuarterlyPaymentsMade" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="TotalRequiredDebtInstrumentQuarterlyPaymentsMade" xlink:title="definition: SubsequentEventLineItems to TotalRequiredDebtInstrumentQuarterlyPaymentsMade" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_MaximumMilestonePaymentObligation" xlink:label="MaximumMilestonePaymentObligation" xlink:title="MaximumMilestonePaymentObligation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="MaximumMilestonePaymentObligation" xlink:title="definition: SubsequentEventLineItems to MaximumMilestonePaymentObligation" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_AggregateRemainingMilestonePaymentObligation" xlink:label="AggregateRemainingMilestonePaymentObligation" xlink:title="AggregateRemainingMilestonePaymentObligation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="AggregateRemainingMilestonePaymentObligation" xlink:title="definition: SubsequentEventLineItems to AggregateRemainingMilestonePaymentObligation" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="DebtInstrumentInterestRateStatedPercentage" xlink:title="DebtInstrumentInterestRateStatedPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="DebtInstrumentInterestRateStatedPercentage" xlink:title="definition: SubsequentEventLineItems to DebtInstrumentInterestRateStatedPercentage" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RoyaltiesCurrentlyPayableNextTwelveMonths" xlink:label="RoyaltiesCurrentlyPayableNextTwelveMonths" xlink:title="RoyaltiesCurrentlyPayableNextTwelveMonths" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="RoyaltiesCurrentlyPayableNextTwelveMonths" xlink:title="definition: SubsequentEventLineItems to RoyaltiesCurrentlyPayableNextTwelveMonths" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RoyaltiesCurrentlyPayableYearTwo" xlink:label="RoyaltiesCurrentlyPayableYearTwo" xlink:title="RoyaltiesCurrentlyPayableYearTwo" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="RoyaltiesCurrentlyPayableYearTwo" xlink:title="definition: SubsequentEventLineItems to RoyaltiesCurrentlyPayableYearTwo" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RoyaltiesCurrentlyPayableYearThree" xlink:label="RoyaltiesCurrentlyPayableYearThree" xlink:title="RoyaltiesCurrentlyPayableYearThree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="RoyaltiesCurrentlyPayableYearThree" xlink:title="definition: SubsequentEventLineItems to RoyaltiesCurrentlyPayableYearThree" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CommittedFundingUnderRIPSA" xlink:label="CommittedFundingUnderRIPSA" xlink:title="CommittedFundingUnderRIPSA" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="CommittedFundingUnderRIPSA" xlink:title="definition: SubsequentEventLineItems to CommittedFundingUnderRIPSA" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CommitmentAmountInExchangeForConvertiblePreferenceShares" xlink:label="CommitmentAmountInExchangeForConvertiblePreferenceShares" xlink:title="CommitmentAmountInExchangeForConvertiblePreferenceShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="CommitmentAmountInExchangeForConvertiblePreferenceShares" xlink:title="definition: SubsequentEventLineItems to CommitmentAmountInExchangeForConvertiblePreferenceShares" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_LiquidationPreferenceConversionRate" xlink:label="LiquidationPreferenceConversionRate" xlink:title="LiquidationPreferenceConversionRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="LiquidationPreferenceConversionRate" xlink:title="definition: SubsequentEventLineItems to LiquidationPreferenceConversionRate" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_ThirdPartyOwnershipOfSubsidiaryPercentage" xlink:label="ThirdPartyOwnershipOfSubsidiaryPercentage" xlink:title="ThirdPartyOwnershipOfSubsidiaryPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="ThirdPartyOwnershipOfSubsidiaryPercentage" xlink:title="definition: SubsequentEventLineItems to ThirdPartyOwnershipOfSubsidiaryPercentage" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_OwnershipOfSubsidiaryPercentage" xlink:label="OwnershipOfSubsidiaryPercentage" xlink:title="OwnershipOfSubsidiaryPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="OwnershipOfSubsidiaryPercentage" xlink:title="definition: SubsequentEventLineItems to OwnershipOfSubsidiaryPercentage" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTable" xlink:label="SubsequentEventTable" xlink:title="SubsequentEventTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="SubsequentEventLineItems" xlink:to="SubsequentEventTable" xlink:title="definition: SubsequentEventLineItems to SubsequentEventTable" order="18.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="SubsequentEventTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: SubsequentEventTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_DermavantMember" xlink:label="DermavantMember" xlink:title="DermavantMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DermavantMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DermavantMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="TypeOfArrangementAxis" xlink:title="TypeOfArrangementAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="SubsequentEventTable" xlink:to="TypeOfArrangementAxis" xlink:title="definition: SubsequentEventTable to TypeOfArrangementAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="ArrangementsAndNonarrangementTransactionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypeOfArrangementAxis" xlink:to="ArrangementsAndNonarrangementTransactionsMember_2" xlink:title="definition: TypeOfArrangementAxis to ArrangementsAndNonarrangementTransactionsMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_FundingAgreementWithNovaQuestMember" xlink:label="FundingAgreementWithNovaQuestMember" xlink:title="FundingAgreementWithNovaQuestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="FundingAgreementWithNovaQuestMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to FundingAgreementWithNovaQuestMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_NovaQuestAgreementAmendmentMember" xlink:label="NovaQuestAgreementAmendmentMember" xlink:title="NovaQuestAgreementAmendmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="NovaQuestAgreementAmendmentMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to NovaQuestAgreementAmendmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CreditFacilityWithXYQLuxcoMember" xlink:label="CreditFacilityWithXYQLuxcoMember" xlink:title="CreditFacilityWithXYQLuxcoMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="CreditFacilityWithXYQLuxcoMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to CreditFacilityWithXYQLuxcoMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_CreditFacilityAmendmentMember" xlink:label="CreditFacilityAmendmentMember" xlink:title="CreditFacilityAmendmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="CreditFacilityAmendmentMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to CreditFacilityAmendmentMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:label="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:title="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to RevenueInterestPurchaseAndSaleAgreementWithXYQLuxcoNovaQuestMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_RIPSAAmendmentMember" xlink:label="RIPSAAmendmentMember" xlink:title="RIPSAAmendmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="RIPSAAmendmentMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to RIPSAAmendmentMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_SumitomoMember" xlink:label="SumitomoMember" xlink:title="SumitomoMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ArrangementsAndNonarrangementTransactionsMember" xlink:to="SumitomoMember" xlink:title="definition: ArrangementsAndNonarrangementTransactionsMember to SumitomoMember" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="SubsequentEventTable" xlink:to="StatementScenarioAxis" xlink:title="definition: SubsequentEventTable to StatementScenarioAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain_2" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain_2" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioForecastMember" xlink:label="ScenarioForecastMember" xlink:title="ScenarioForecastMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScenarioUnspecifiedDomain" xlink:to="ScenarioForecastMember" xlink:title="definition: ScenarioUnspecifiedDomain to ScenarioForecastMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="SubsequentEventTypeAxis" xlink:title="SubsequentEventTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="SubsequentEventTable" xlink:to="SubsequentEventTypeAxis" xlink:title="definition: SubsequentEventTable to SubsequentEventTypeAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="SubsequentEventTypeDomain" xlink:title="SubsequentEventTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SubsequentEventTypeAxis" xlink:to="SubsequentEventTypeDomain" xlink:title="definition: SubsequentEventTypeAxis to SubsequentEventTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="SubsequentEventTypeDomain_2" xlink:title="SubsequentEventTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SubsequentEventTypeAxis" xlink:to="SubsequentEventTypeDomain_2" xlink:title="definition: SubsequentEventTypeAxis to SubsequentEventTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubsequentEventMember" xlink:label="SubsequentEventMember" xlink:title="SubsequentEventMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventTypeDomain" xlink:to="SubsequentEventMember" xlink:title="definition: SubsequentEventTypeDomain to SubsequentEventMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:label="ShareRepurchaseProgramAxis" xlink:title="ShareRepurchaseProgramAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="SubsequentEventTable" xlink:to="ShareRepurchaseProgramAxis" xlink:title="definition: SubsequentEventTable to ShareRepurchaseProgramAxis" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="ShareRepurchaseProgramDomain" xlink:title="ShareRepurchaseProgramDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ShareRepurchaseProgramAxis" xlink:to="ShareRepurchaseProgramDomain" xlink:title="definition: ShareRepurchaseProgramAxis to ShareRepurchaseProgramDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="ShareRepurchaseProgramDomain_2" xlink:title="ShareRepurchaseProgramDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ShareRepurchaseProgramAxis" xlink:to="ShareRepurchaseProgramDomain_2" xlink:title="definition: ShareRepurchaseProgramAxis to ShareRepurchaseProgramDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_StockRepurchaseProgramMember" xlink:label="StockRepurchaseProgramMember" xlink:title="StockRepurchaseProgramMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareRepurchaseProgramDomain" xlink:to="StockRepurchaseProgramMember" xlink:title="definition: ShareRepurchaseProgramDomain to StockRepurchaseProgramMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementAbstract" xlink:label="IncomeStatementAbstract" xlink:title="IncomeStatementAbstract" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_GainLossOnFairValueOfDebtAndLiabilityInstruments" xlink:label="GainLossOnFairValueOfDebtAndLiabilityInstruments" xlink:title="GainLossOnFairValueOfDebtAndLiabilityInstruments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementAbstract" xlink:to="GainLossOnFairValueOfDebtAndLiabilityInstruments" xlink:title="definition: IncomeStatementAbstract to GainLossOnFairValueOfDebtAndLiabilityInstruments" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAbstract" xlink:label="LiabilitiesAbstract" xlink:title="LiabilitiesAbstract" />
    <link:loc xlink:type="locator" xlink:href="roiv-20240331.xsd#roiv_LiabilityInstrumentsMeasuredAtFairValue" xlink:label="LiabilityInstrumentsMeasuredAtFairValue" xlink:title="LiabilityInstrumentsMeasuredAtFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAbstract" xlink:to="LiabilityInstrumentsMeasuredAtFairValue" xlink:title="definition: LiabilitiesAbstract to LiabilityInstrumentsMeasuredAtFairValue" order="1.0" />
  </link:definitionLink>
</link:linkbase>
