<?xml version="1.0" encoding="US-ASCII"?>
<!-- DFIN New ActiveDisclosure (SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date :2023-10-25T08:32:25.9009+00:00 -->
<!-- Copyright (c) 2023 Donnelly Financial Solutions, Inc. All Rights Reserved. -->
<xsd:schema targetNamespace="http://www.alkermes.com/20230930" attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2022-03-31" xmlns:country="http://xbrl.sec.gov/country/2023" xmlns:ecd-sub="http://xbrl.sec.gov/ecd-sub/2023" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:dei="http://xbrl.sec.gov/dei/2023" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:enum2="http://xbrl.org/2020/extensible-enumerations-2.0" xmlns:srt="http://fasb.org/srt/2023" xmlns:us-gaap="http://fasb.org/us-gaap/2023" xmlns:alks="http://www.alkermes.com/20230930" xmlns:xlink="http://www.w3.org/1999/xlink">
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/instance"/>
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/linkbase"/>
  <xsd:import schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" namespace="http://xbrl.org/2005/xbrldt"/>
  <xsd:import schemaLocation="https://xbrl.sec.gov/dei/2023/dei-2023.xsd" namespace="http://xbrl.sec.gov/dei/2023"/>
  <xsd:import schemaLocation="https://www.xbrl.org/2020/extensible-enumerations-2.0.xsd" namespace="http://xbrl.org/2020/extensible-enumerations-2.0"/>
  <xsd:import schemaLocation="https://xbrl.sec.gov/ecd/2023/ecd-sub-2023.xsd" namespace="http://xbrl.sec.gov/ecd-sub/2023"/>
  <xsd:import schemaLocation="https://www.xbrl.org/dtr/type/2022-03-31/types.xsd" namespace="http://www.xbrl.org/dtr/type/2022-03-31"/>
  <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd" namespace="http://fasb.org/us-gaap/2023"/>
  <xsd:import schemaLocation="https://xbrl.sec.gov/country/2023/country-2023.xsd" namespace="http://xbrl.sec.gov/country/2023"/>
  <xsd:import schemaLocation="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd" namespace="http://fasb.org/srt/2023"/>
  <xsd:annotation>
    <xsd:appinfo>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="alks-20230930_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:title="Labels link" xlink:type="simple"/>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="alks-20230930_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:title="Presentation link" xlink:type="simple"/>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="alks-20230930_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:title="Definition link" xlink:type="simple"/>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="alks-20230930_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:title="Calculation link" xlink:type="simple"/>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DocumentDocumentAndEntityInformation" id="Role_DocumentDocumentAndEntityInformation">
        <link:definition>100000 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_StatementCONDENSEDCONSOLIDATEDBALANCESHEETSUnaudited" id="Role_StatementCONDENSEDCONSOLIDATEDBALANCESHEETSUnaudited">
        <link:definition>100010 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureLeasesSummaryOfFutureLeasePaymentsUnderNoncancelableLeasesDetails2" id="DisclosureLeasesSummaryOfFutureLeasePaymentsUnderNoncancelableLeasesDetails2">
        <link:definition>100020 - Disclosure - Leases - Summary of Future Lease Payments Under Non-Cancelable Leases (Details) 2</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_StatementCONDENSEDCONSOLIDATEDBALANCESHEETSParentheticalUnaudited" id="Role_StatementCONDENSEDCONSOLIDATEDBALANCESHEETSParentheticalUnaudited">
        <link:definition>100030 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/StatementCondensedConsolidatedStatementsOfOperationsAndComprehensiveIncomeLossUnaudited1" id="StatementCondensedConsolidatedStatementsOfOperationsAndComprehensiveIncomeLossUnaudited1">
        <link:definition>100040 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/StatementCondensedConsolidatedStatementsOfOperationsAndComprehensiveIncomeLossUnauditedParenthetical" id="StatementCondensedConsolidatedStatementsOfOperationsAndComprehensiveIncomeLossUnauditedParenthetical">
        <link:definition>100050 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (unaudited) (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited" id="Role_StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited">
        <link:definition>100060 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITYUnaudited" id="Role_StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITYUnaudited">
        <link:definition>100070 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITYUnauditedParenthetical" id="Role_StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITYUnauditedParenthetical">
        <link:definition>100080 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (unaudited) (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureTheCompany" id="Role_DisclosureTheCompany">
        <link:definition>995455 - Disclosure - The Company</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies" id="Role_DisclosureSummaryOfSignificantAccountingPolicies">
        <link:definition>995465 - Disclosure - Summary of Significant Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureRevenueFromContractsWithCustomers" id="Role_DisclosureRevenueFromContractsWithCustomers">
        <link:definition>995475 - Disclosure - Revenue from Contracts with Customers</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInvestments" id="Role_DisclosureInvestments">
        <link:definition>995485 - Disclosure - Investments</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureFairValue" id="Role_DisclosureFairValue">
        <link:definition>995495 - Disclosure - Fair Value</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInventory" id="Role_DisclosureInventory">
        <link:definition>995505 - Disclosure - Inventory</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosurePropertyPlantAndEquipment" id="Role_DisclosurePropertyPlantAndEquipment">
        <link:definition>995515 - Disclosure - Property, Plant and Equipment</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureGoodwillAndIntangibleAssets" id="Role_DisclosureGoodwillAndIntangibleAssets">
        <link:definition>995525 - Disclosure - Goodwill and Intangible Assets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureLeases" id="Role_DisclosureLeases">
        <link:definition>995535 - Disclosure - Leases</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureAccountsPayableAndAccruedExpenses" id="Role_DisclosureAccountsPayableAndAccruedExpenses">
        <link:definition>995545 - Disclosure - Accounts Payable and Accrued Expenses</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureLongTermDebt" id="Role_DisclosureLongTermDebt">
        <link:definition>995555 - Disclosure - Long-term Debt</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureShareBasedCompensation" id="Role_DisclosureShareBasedCompensation">
        <link:definition>995565 - Disclosure - Share-based Compensation</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureEarningsLossPerShare" id="DisclosureEarningsLossPerShare">
        <link:definition>995575 - Disclosure - Earnings (Loss) Per Share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureIncomeTaxes" id="Role_DisclosureIncomeTaxes">
        <link:definition>995585 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureRestructuring" id="DisclosureRestructuring">
        <link:definition>995595 - Disclosure - Restructuring</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureCommitmentsAndContingentLiabilities" id="Role_DisclosureCommitmentsAndContingentLiabilities">
        <link:definition>995605 - Disclosure - Commitments and Contingent Liabilities</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureSubsequentEvent" id="DisclosureSubsequentEvent">
        <link:definition>995615 - Disclosure - Subsequent Event</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesPolicies" id="Role_DisclosureSummaryOfSignificantAccountingPoliciesPolicies">
        <link:definition>995625 - Disclosure - Summary of Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureRevenueFromContractsWithCustomersTables" id="Role_DisclosureRevenueFromContractsWithCustomersTables">
        <link:definition>995635 - Disclosure - Revenue from Contracts with Customers (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInvestmentsTables" id="Role_DisclosureInvestmentsTables">
        <link:definition>995645 - Disclosure - Investments (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureFairValueTables" id="Role_DisclosureFairValueTables">
        <link:definition>995655 - Disclosure - Fair Value (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInventoryTables" id="Role_DisclosureInventoryTables">
        <link:definition>995665 - Disclosure - Inventory (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosurePropertyPlantAndEquipmentTables" id="Role_DisclosurePropertyPlantAndEquipmentTables">
        <link:definition>995675 - Disclosure - Property, Plant and Equipment (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureGoodwillAndIntangibleAssetsTables" id="Role_DisclosureGoodwillAndIntangibleAssetsTables">
        <link:definition>995685 - Disclosure - Goodwill and Intangible Assets (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureLeasesTables" id="Role_DisclosureLeasesTables">
        <link:definition>995695 - Disclosure - Leases (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureAccountsPayableAndAccruedExpensesTables" id="Role_DisclosureAccountsPayableAndAccruedExpensesTables">
        <link:definition>995705 - Disclosure - Accounts Payable and Accrued Expenses (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureLongTermDebtTables" id="Role_DisclosureLongTermDebtTables">
        <link:definition>995715 - Disclosure - Long-term Debt (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureShareBasedCompensationTables" id="Role_DisclosureShareBasedCompensationTables">
        <link:definition>995725 - Disclosure - Share-based Compensation (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureEarningsLossPerShareTables" id="DisclosureEarningsLossPerShareTables">
        <link:definition>995735 - Disclosure - Earnings (Loss) Per Share (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureRestructuringTables" id="DisclosureRestructuringTables">
        <link:definition>995745 - Disclosure - Restructuring (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails" id="Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails">
        <link:definition>995755 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureRevenueFromContractsWithCustomersScheduleOfDisaggregationOfRevenueDetails" id="Role_DisclosureRevenueFromContractsWithCustomersScheduleOfDisaggregationOfRevenueDetails">
        <link:definition>995765 - Disclosure - Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureRevenueFromContractsWithCustomersScheduleOfManufacturingAndRoyaltyRevenuesDetails" id="Role_DisclosureRevenueFromContractsWithCustomersScheduleOfManufacturingAndRoyaltyRevenuesDetails">
        <link:definition>995775 - Disclosure - Revenue from Contracts with Customers - Schedule of Manufacturing and Royalty Revenues (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureRevenueFromContractsWithCustomersAdditionalInformationDetails" id="Role_DisclosureRevenueFromContractsWithCustomersAdditionalInformationDetails">
        <link:definition>995785 - Disclosure - Revenue from Contracts with Customers - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureRevenueFromContractsWithCustomersScheduleOfContractAssetsAndContractLiabilitiesDetails" id="Role_DisclosureRevenueFromContractsWithCustomersScheduleOfContractAssetsAndContractLiabilitiesDetails">
        <link:definition>995795 - Disclosure - Revenue from Contracts with Customers - Schedule of Contract Assets and Contract Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInvestmentsScheduleOfInvestmentsDetails" id="Role_DisclosureInvestmentsScheduleOfInvestmentsDetails">
        <link:definition>995805 - Disclosure - Investments - Schedule of Investments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInvestmentsAdditionalInformationDetails" id="Role_DisclosureInvestmentsAdditionalInformationDetails">
        <link:definition>995815 - Disclosure - Investments - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInvestmentsScheduleOfProceedsFromSalesAndMaturitiesOfMarketableSecuritiesPlusResultingRealizedGainsAndLossesDetails" id="Role_DisclosureInvestmentsScheduleOfProceedsFromSalesAndMaturitiesOfMarketableSecuritiesPlusResultingRealizedGainsAndLossesDetails">
        <link:definition>995825 - Disclosure - Investments - Schedule of Proceeds from Sales and Maturities of Marketable Securities Plus Resulting Realized Gains and Losses (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInvestmentsScheduleOfContractualMaturitiesOfAvailableForSaleAndHeldToMaturitySecuritiesDetails" id="Role_DisclosureInvestmentsScheduleOfContractualMaturitiesOfAvailableForSaleAndHeldToMaturitySecuritiesDetails">
        <link:definition>995835 - Disclosure - Investments - Schedule of Contractual Maturities of Available-for-Sale and Held-to-Maturity Securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureFairValueSummaryOfCompanySAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails" id="Role_DisclosureFairValueSummaryOfCompanySAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails">
        <link:definition>995845 - Disclosure - Fair Value - Summary of the Company's Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureFairValueAdditionalInformationDetails" id="Role_DisclosureFairValueAdditionalInformationDetails">
        <link:definition>995855 - Disclosure - Fair Value - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureFairValueRollforwardOfFairValueOfAssetsDeterminedUsingLevel3InputsDetails" id="Role_DisclosureFairValueRollforwardOfFairValueOfAssetsDeterminedUsingLevel3InputsDetails">
        <link:definition>995865 - Disclosure - Fair Value - Rollforward of the Fair Value of the Assets Determined using Level 3 Inputs (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInventoryScheduleOfInventoriesDetails" id="Role_DisclosureInventoryScheduleOfInventoriesDetails">
        <link:definition>995875 - Disclosure - Inventory - Schedule of Inventories (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureInventoryScheduleOfInventoriesParentheticalDetails" id="Role_DisclosureInventoryScheduleOfInventoriesParentheticalDetails">
        <link:definition>995885 - Disclosure - Inventory - Schedule of Inventories (Parenthetical) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosurePropertyPlantAndEquipmentScheduleOfPropertyPlantAndEquipmentDetails" id="Role_DisclosurePropertyPlantAndEquipmentScheduleOfPropertyPlantAndEquipmentDetails">
        <link:definition>995895 - Disclosure - Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosurePropertyPlantAndEquipmentAdditionalInformationDetails" id="DisclosurePropertyPlantAndEquipmentAdditionalInformationDetails">
        <link:definition>995905 - Disclosure - Property, Plant and Equipment - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureGoodwillAndIntangibleAssetsScheduleOfGoodwillAndIntangibleAssetsDetails" id="Role_DisclosureGoodwillAndIntangibleAssetsScheduleOfGoodwillAndIntangibleAssetsDetails">
        <link:definition>995915 - Disclosure - Goodwill and Intangible Assets - Schedule of Goodwill and Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureGoodwillAndIntangibleAssetsAdditionalInformationDetails" id="Role_DisclosureGoodwillAndIntangibleAssetsAdditionalInformationDetails">
        <link:definition>995925 - Disclosure - Goodwill and Intangible Assets - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureLeasesSummaryOfFutureLeasePaymentsUnderNonCancelableLeasesDetails" id="Role_DisclosureLeasesSummaryOfFutureLeasePaymentsUnderNonCancelableLeasesDetails">
        <link:definition>995935 - Disclosure - Leases - Summary of Future Lease Payments Under Non-Cancelable Leases (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureLeasesAdditionalInformationDetails" id="Role_DisclosureLeasesAdditionalInformationDetails">
        <link:definition>995945 - Disclosure - Leases - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureAccountsPayableAndAccruedExpensesScheduleOfAccountsPayableAndAccruedExpensesDetails" id="Role_DisclosureAccountsPayableAndAccruedExpensesScheduleOfAccountsPayableAndAccruedExpensesDetails">
        <link:definition>995955 - Disclosure - Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureAccountsPayableAndAccruedExpensesSummaryOfCurrentProvisionForSalesDiscountsAllowancesAndReservesDetails" id="Role_DisclosureAccountsPayableAndAccruedExpensesSummaryOfCurrentProvisionForSalesDiscountsAllowancesAndReservesDetails">
        <link:definition>995965 - Disclosure - Accounts Payable and Accrued Expenses - Summary of Current Provision for Sales, Discounts, Allowances and Reserves (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureAccountsPayableAndAccruedExpensesAdditionalInformationDetails" id="DisclosureAccountsPayableAndAccruedExpensesAdditionalInformationDetails">
        <link:definition>995975 - Disclosure - Accounts Payable and Accrued Expenses - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureLongTermDebtScheduleOfLongTermDebtDetails" id="Role_DisclosureLongTermDebtScheduleOfLongTermDebtDetails">
        <link:definition>995985 - Disclosure - Long-term Debt - Schedule of Long-term Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureLongTermDebtAdditionalInformationDetails" id="Role_DisclosureLongTermDebtAdditionalInformationDetails">
        <link:definition>995995 - Disclosure - Long-term Debt - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureShareBasedCompensationScheduleOfShareBasedCompensationExpenseDetails" id="Role_DisclosureShareBasedCompensationScheduleOfShareBasedCompensationExpenseDetails">
        <link:definition>996005 - Disclosure - Share-based Compensation - Schedule of Share-based Compensation Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureShareBasedCompensationAdditionalInformationDetails" id="Role_DisclosureShareBasedCompensationAdditionalInformationDetails">
        <link:definition>996015 - Disclosure - Share-based Compensation - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureEarningsLossPerShareScheduleOfEarningsPerShareBasicAndDilutedDetails" id="DisclosureEarningsLossPerShareScheduleOfEarningsPerShareBasicAndDilutedDetails">
        <link:definition>996025 - Disclosure - Earnings (Loss) Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureEarningsLossPerShareScheduleOfAntidilutiveOutstandingCommonShareEquivalentExcludedFromCalculationOfNetEarningsLossPerOrdinarySh" id="DisclosureEarningsLossPerShareScheduleOfAntidilutiveOutstandingCommonShareEquivalentExcludedFromCalculationOfNetEarningsLossPerOrdinarySh">
        <link:definition>996035 - Disclosure - Earnings (Loss) Per Share - Schedule of Anti-Dilutive Outstanding Common Share Equivalent Excluded from Calculation of Net Earnings (Loss) Per Ordinary Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureIncomeTaxesAdditionalInformationDetails" id="Role_DisclosureIncomeTaxesAdditionalInformationDetails">
        <link:definition>996045 - Disclosure - Income Taxes - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureRestructuringScheduleOfRestructuringActivityDetails" id="DisclosureRestructuringScheduleOfRestructuringActivityDetails">
        <link:definition>996055 - Disclosure - Restructuring - Schedule of Restructuring Activity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/DisclosureRestructuringAdditionalInformationDetails" id="DisclosureRestructuringAdditionalInformationDetails">
        <link:definition>996065 - Disclosure - Restructuring - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.alkermes.com/20230930/taxonomy/role/Role_DisclosureCommitmentsAndContingentLiabilitiesAdditionalInformationDetails" id="Role_DisclosureCommitmentsAndContingentLiabilitiesAdditionalInformationDetails">
        <link:definition>996075 - Disclosure - Commitments and Contingent Liabilities - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element id="alks_SynchronicityPharmaIncMember" name="SynchronicityPharmaIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionGreaterThan12MonthsAccumulatedLossNonCurrent" name="DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionGreaterThan12MonthsAccumulatedLossNonCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_ScheduleOfAccruedSalesDiscountsAllowancesAndReservesTableTextBlock" name="ScheduleOfAccruedSalesDiscountsAllowancesAndReservesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_BackRoyaltiesLatePaymentInterest" name="BackRoyaltiesLatePaymentInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_ConvertiblePromissoryNotesMember" name="ConvertiblePromissoryNotesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_NumberOfUnrealizedInvestmentSecurities" name="NumberOfUnrealizedInvestmentSecurities" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_MilestonePaymentsReceivable" name="MilestonePaymentsReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_MarketableSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses" name="MarketableSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_IncomeTaxesTable" name="IncomeTaxesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_ManufacturingRevenueMember" name="ManufacturingRevenueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_MarketableSecuritiesAtAmortizedCost" name="MarketableSecuritiesAtAmortizedCost" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_CommitmentsAndContingenciesTable" name="CommitmentsAndContingenciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_ContractWithCustomerLiabilityAdditions" name="ContractWithCustomerLiabilityAdditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_PaymentsForRestructuringOutplacementServices" name="PaymentsForRestructuringOutplacementServices" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_AccruedSalesDiscountsAllowancesAndReserves" name="AccruedSalesDiscountsAllowancesAndReserves" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_MarketableSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses" name="MarketableSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_StateMedicaidRebatesMember" name="StateMedicaidRebatesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_LYBALVIMember" name="LYBALVIMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_ArbitrationAwardAmountPaid" name="ArbitrationAwardAmountPaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_WorldwideBasedRoyaltiesMember" name="WorldwideBasedRoyaltiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_PaymentsForRestructuringBenefits" name="PaymentsForRestructuringBenefits" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_CommitmentOnEquityMethodInvestment" name="CommitmentOnEquityMethodInvestment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_AdditionalRevenuePaid" name="AdditionalRevenuePaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_AdditionalRevenueToBePaid" name="AdditionalRevenueToBePaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_TwentyTwentySixTermLoansMember" name="TwentyTwentySixTermLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_LongTermInvestmentSecuritiesUnrealizedGainLoss" name="LongTermInvestmentSecuritiesUnrealizedGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_MarketableSecuritiesRealizedLoss" name="MarketableSecuritiesRealizedLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_PaymentMadeForLicensedIntellectualProperty" name="PaymentMadeForLicensedIntellectualProperty" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_NumberOfInvestmentSecurities" name="NumberOfInvestmentSecurities" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_PercentageOfInvestmentSecuritiesAvailableForSaleUnrealizedLossPosition2" name="PercentageOfInvestmentSecuritiesAvailableForSaleUnrealizedLossPosition2" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="alks_RepaymentOfRoyaltyRevenue" name="RepaymentOfRoyaltyRevenue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_PotentialAdditionalAwardToBePaid" name="PotentialAdditionalAwardToBePaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_ReturnOfInvestments" name="ReturnOfInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_AccountsPayableAndAccruedExpensesTable" name="AccountsPayableAndAccruedExpensesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_ResearchAndDevelopmentMember" name="ResearchAndDevelopmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_IncreaseDecreaseInAccruedSalesDiscountAllowancesAndReserves" name="IncreaseDecreaseInAccruedSalesDiscountAllowancesAndReserves" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_ManufacturedProductAndRoyaltyMember" name="ManufacturedProductAndRoyaltyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_JanssenPharmaceuticaNVMember" name="JanssenPharmaceuticaNVMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_PercentageOfInvestmentSecuritiesAvailableForSaleUnrealizedLossPosition" name="PercentageOfInvestmentSecuritiesAvailableForSaleUnrealizedLossPosition" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="alks_AmpyraMember" name="AmpyraMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_NumberOfLicenseAgreementsPartiallyTerminated" name="NumberOfLicenseAgreementsPartiallyTerminated" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_ConsiderationExpectedToReceiveYear" name="ConsiderationExpectedToReceiveYear" type="xbrli:gYearMonthItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_MilestonePaymentsReceived" name="MilestonePaymentsReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_ManufacturingProcessPeriod" name="ManufacturingProcessPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_AdditionalAwardPaid" name="AdditionalAwardPaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_ProceedsAndRealizedGainLossOnMarketableSecuritiesTableTextBlock" name="ProceedsAndRealizedGainLossOnMarketableSecuritiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_OtherMember" name="OtherMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_ReceiptOfCompanyStockForExerciseOfStockOptionsOrToSatisfyMinimumTaxWithholdingObligationsRelatedToStockBasedAwardsValue" name="ReceiptOfCompanyStockForExerciseOfStockOptionsOrToSatisfyMinimumTaxWithholdingObligationsRelatedToStockBasedAwardsValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_RepaymentOfRevenue" name="RepaymentOfRevenue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_TwoThousandAndEighteenStockOptionAndIncentivePlanMember" name="TwoThousandAndEighteenStockOptionAndIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_LiborMember" name="LiborMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_OtherProductsAndServicesMember" name="OtherProductsAndServicesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_AccountsPayableAndAccruedExpensesLineItems" name="AccountsPayableAndAccruedExpensesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_LongTermInvestmentSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses" name="LongTermInvestmentSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_ProductDiscountsMember" name="ProductDiscountsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_BaudaxBioIncMember" name="BaudaxBioIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_IncreaseDecreaseInRightOfUseAsset" name="IncreaseDecreaseInRightOfUseAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_ReceiptOfCompanyStockForExerciseOfStockOptionsOrToSatisfyMinimumTaxWithholdingObligationsRelatedToStockBasedAwardsShares" name="ReceiptOfCompanyStockForExerciseOfStockOptionsOrToSatisfyMinimumTaxWithholdingObligationsRelatedToStockBasedAwardsShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_RestructuringAndRelatedActivitiesInitiationMonthAndYear" name="RestructuringAndRelatedActivitiesInitiationMonthAndYear" type="xbrli:gYearMonthItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_IncomeTaxesLineItems" name="IncomeTaxesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLossCurrent" name="DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLossCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_RoyaltyRevenueRelatedToBackRoyalties" name="RoyaltyRevenueRelatedToBackRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_ContractLiabilitiesMember" name="ContractLiabilitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" name="LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_IncreaseDecreaseInOperatingLeaseLiabilities" name="IncreaseDecreaseInOperatingLeaseLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_FountainHealthcarePartnersIiLpOfIrelandMember" name="FountainHealthcarePartnersIiLpOfIrelandMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_MeloxicamProductMember" name="MeloxicamProductMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_ContractWithCustomerLiabilityOtherExpenseIncomeNetRecognized" name="ContractWithCustomerLiabilityOtherExpenseIncomeNetRecognized" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_LongTermInvestmentSecuritiesContinuousUnrealizedLossPositionMoreThan12MonthsAggregateLosses" name="LongTermInvestmentSecuritiesContinuousUnrealizedLossPositionMoreThan12MonthsAggregateLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_AdditionalSoughtValueForDamages" name="AdditionalSoughtValueForDamages" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_FairValueRecurringBasisAssetsOrLiabilitiesTransfersBetweenLevelTwoToLevelOne" name="FairValueRecurringBasisAssetsOrLiabilitiesTransfersBetweenLevelTwoToLevelOne" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLossNoncurrent" name="DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLossNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLossCurrent" name="DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLossCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_VivitrolMember" name="VivitrolMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_RISPERDALCONSTAMember" name="RISPERDALCONSTAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_EquityMethodCommitment" name="EquityMethodCommitment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_PercentageOfReductionInWorkForce" name="PercentageOfReductionInWorkForce" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_ProceedsFromContingentConsideration" name="ProceedsFromContingentConsideration" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_CommitmentsAndContingenciesLineItems" name="CommitmentsAndContingenciesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_MedicaidRebateMember" name="MedicaidRebateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_MedicarePartDMember" name="MedicarePartDMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_BiogenMember" name="BiogenMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_DebtInstrumentVariableRateBasisFloor" name="DebtInstrumentVariableRateBasisFloor" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTaxNoncurrent" name="AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTaxNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_VumerityMember" name="VumerityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_FairValueRecurringBasisAssetsOrLiabilitiesTransfersBetweenLevelOneToLevelTwo" name="FairValueRecurringBasisAssetsOrLiabilitiesTransfersBetweenLevelOneToLevelTwo" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_ArbitrationAwardAmountPayable" name="ArbitrationAwardAmountPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_LongTermInvestmentAmortizedCost" name="LongTermInvestmentAmortizedCost" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_AristadaAndAristadaInitioMember" name="AristadaAndAristadaInitioMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetImpairmentOfCorporateDebtSecurity" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetImpairmentOfCorporateDebtSecurity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTaxCurrent" name="AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTaxCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_MarketableInvestmentsSecuritiesUnrealizedGainLoss" name="MarketableInvestmentsSecuritiesUnrealizedGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_LongActingINVEGAProductsMember" name="LongActingINVEGAProductsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_MarketableSecuritiesRealizedGain" name="MarketableSecuritiesRealizedGain" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_InventoryFinishedGoodsNetOfReservesLocatedAtThirdPartyWarehouseAndShippingServiceProvider" name="InventoryFinishedGoodsNetOfReservesLocatedAtThirdPartyWarehouseAndShippingServiceProvider" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="alks_DebtInstrumentIncrementalCapacitySubjectToSatisfactionOfCertainConditions" name="DebtInstrumentIncrementalCapacitySubjectToSatisfactionOfCertainConditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_UsBasedRoyaltiesMember" name="UsBasedRoyaltiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="alks_RiskAndUncertaintiesPolicyTextBlock" name="RiskAndUncertaintiesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="alks_FundingCommitmentAsPercentageOfPartnershipsFunding" name="FundingCommitmentAsPercentageOfPartnershipsFunding" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="alks_PaymentsForRestructuringSeverance" name="PaymentsForRestructuringSeverance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="alks_FurnitureFixtureAndEquipmentMember" name="FurnitureFixtureAndEquipmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
</xsd:schema>
