<?xml version="1.0" encoding="utf-8"?>
<!--Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 09-June-2026 [08:15:41] {PM}-->
<schema targetNamespace="http://www.steris.com/20260331" elementFormDefault="qualified" xmlns:ste="http://www.steris.com/20260331" xmlns="http://www.w3.org/2001/XMLSchema" 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:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:us-gaap="http://fasb.org/us-gaap/2025" xmlns:country="http://xbrl.sec.gov/country/2025" xmlns:dei="http://xbrl.sec.gov/dei/2025" xmlns:us-types="http://fasb.org/us-types/2025" xmlns:deprecated="http://www.xbrl.org/2009/arcrole/fact-explanatoryFact" xmlns:srt="http://fasb.org/srt/2025" xmlns:srt-types="http://fasb.org/srt-types/2025" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31">
  <annotation>
    <appinfo>
      <link:linkbase id="lnk" >
        <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#PvpDisclosure" roleURI="http://xbrl.sec.gov/ecd/role/PvpDisclosure"  />
        <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#IndividualsOnly" roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly"  />
        <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#PvpAdjustmentsOnly" roleURI="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly"  />
        <link:presentationLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/PvpDisclosure" >
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllIndividualsMember" xlink:label="loc_ecd_AllIndividualsMember_138284342" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_DanielJ.CarestioMember" xlink:label="loc_STE_DanielJ.CarestioMember_138284346" />
          <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ecd_AllIndividualsMember_138284342" xlink:to="loc_STE_DanielJ.CarestioMember_138284346" order="100" preferredLabel="http://www.xbrl.org/2003/role/label" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_WalterMRosebroughJr.Member" xlink:label="loc_STE_WalterMRosebroughJr.Member_138284347" />
          <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ecd_AllIndividualsMember_138284342" xlink:to="loc_STE_WalterMRosebroughJr.Member_138284347" order="101" preferredLabel="http://www.xbrl.org/2003/role/label" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllAdjToCompMember" xlink:label="loc_ecd_AllAdjToCompMember_138284386" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_StockAwardsMember" xlink:label="loc_STE_StockAwardsMember_138284348" />
          <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ecd_AllAdjToCompMember_138284386" xlink:to="loc_STE_StockAwardsMember_138284348" order="102" preferredLabel="http://www.xbrl.org/2003/role/label" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_OptionAwardsMember" xlink:label="loc_STE_OptionAwardsMember_138284349" />
          <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ecd_AllAdjToCompMember_138284386" xlink:to="loc_STE_OptionAwardsMember_138284349" order="103" preferredLabel="http://www.xbrl.org/2003/role/label" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_PayVsPerformanceDisclosureLineItems" xlink:label="loc_ecd_PayVsPerformanceDisclosureLineItems_138284382" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_PriorPeerGroupTotalShareHolderReturn" xlink:label="loc_STE_PriorPeerGroupTotalShareHolderReturn_138284396" />
          <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ecd_PayVsPerformanceDisclosureLineItems_138284382" xlink:to="loc_STE_PriorPeerGroupTotalShareHolderReturn_138284396" order="100" preferredLabel="http://www.xbrl.org/2003/role/label" />
        </link:presentationLink>
        <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:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" >
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllIndividualsMember" xlink:label="loc_ecd_AllIndividualsMember_138284342" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_DanielJ.CarestioMember" xlink:label="loc_STE_DanielJ.CarestioMember_138284346" />
          <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember_138284342" xlink:to="loc_STE_DanielJ.CarestioMember_138284346" order="100" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_WalterMRosebroughJr.Member" xlink:label="loc_STE_WalterMRosebroughJr.Member_138284347" />
          <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember_138284342" xlink:to="loc_STE_WalterMRosebroughJr.Member_138284347" order="101" />
        </link:definitionLink>
        <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" >
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllAdjToCompMember" xlink:label="loc_ecd_AllAdjToCompMember_138284386" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_StockAwardsMember" xlink:label="loc_STE_StockAwardsMember_138284348" />
          <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember_138284386" xlink:to="loc_STE_StockAwardsMember_138284348" order="102" />
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_OptionAwardsMember" xlink:label="loc_STE_OptionAwardsMember_138284349" />
          <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember_138284386" xlink:to="loc_STE_OptionAwardsMember_138284349" order="103" />
        </link:definitionLink>
        <link:labelLink xlink:type="extended" xlink:role="http://www.xbrl.org/2003/role/link" >
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_PriorPeerGroupTotalShareHolderReturn" xlink:label="loc_ste_PriorPeerGroupTotalShareHolderReturn" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ste_PriorPeerGroupTotalShareHolderReturn" xml:lang="en-US">Prior Peer Group Total Share holder Return</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ste_PriorPeerGroupTotalShareHolderReturn" xlink:to="lab_ste_PriorPeerGroupTotalShareHolderReturn" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ste_PriorPeerGroupTotalShareHolderReturn" xml:lang="en-US">Prior Peer Group Total Share holder Return</link:label>
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_OptionAwardsMember" xlink:label="loc_ste_OptionAwardsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ste_OptionAwardsMember" xml:lang="en-US">Option Awards [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ste_OptionAwardsMember" xlink:to="lab_ste_OptionAwardsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ste_OptionAwardsMember" xml:lang="en-US">Option awards.</link:label>
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_StockAwardsMember" xlink:label="loc_ste_StockAwardsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ste_StockAwardsMember" xml:lang="en-US">Stock Awards [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ste_StockAwardsMember" xlink:to="lab_ste_StockAwardsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ste_StockAwardsMember" xml:lang="en-US">Stock awards.</link:label>
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_DanielJ.CarestioMember" xlink:label="loc_ste_DanielJ.CarestioMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ste_DanielJ.CarestioMember" xml:lang="en-US">Daniel J. Carestio [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ste_DanielJ.CarestioMember" xlink:to="lab_ste_DanielJ.CarestioMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ste_DanielJ.CarestioMember" xml:lang="en-US">Daniel J. Carestio.</link:label>
          <link:loc xlink:type="locator" xlink:href="ste-20260331.xsd#ste_WalterMRosebroughJr.Member" xlink:label="loc_ste_WalterMRosebroughJr.Member" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ste_WalterMRosebroughJr.Member" xml:lang="en-US">Walter M Rosebrough, Jr. [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ste_WalterMRosebroughJr.Member" xlink:to="lab_ste_WalterMRosebroughJr.Member" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ste_WalterMRosebroughJr.Member" xml:lang="en-US">Walter M Rosebrough, Jr.</link:label>
        </link:labelLink>
      </link:linkbase>
    </appinfo>
  </annotation>
  <import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" />
  <import namespace="http://xbrl.sec.gov/dei/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd" />
  <import namespace="http://xbrl.sec.gov/dei-sub/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-sub-2025.xsd" />
  <import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd" />
  <import namespace="http://fasb.org/srt/2025" schemaLocation="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd" />
  <import namespace="http://fasb.org/srt-types/2025" schemaLocation="https://xbrl.fasb.org/srt/2025/elts/srt-types-2025.xsd" />
  <import namespace="http://xbrl.sec.gov/ecd-sub/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-sub-2025.xsd" />
  <import namespace="http://xbrl.sec.gov/ecd/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd" />
  <import namespace="http://www.xbrl.org/2006/ref" schemaLocation="http://www.xbrl.org/2006/ref-2006-02-27.xsd" />
  <import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <import namespace="http://fasb.org/srt-roles/2025" schemaLocation="https://xbrl.fasb.org/srt/2025/elts/srt-roles-2025.xsd" />
  <element name="PayVsPerformanceDisclosureAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ste_PayVsPerformanceDisclosureAbstract" substitutionGroup="xbrli:item" />
  <element name="OptionAwardsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ste_OptionAwardsMember" substitutionGroup="xbrli:item" />
  <element name="StockAwardsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ste_StockAwardsMember" substitutionGroup="xbrli:item" />
  <element name="DanielJ.CarestioMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ste_DanielJ.CarestioMember" substitutionGroup="xbrli:item" />
  <element name="WalterMRosebroughJr.Member" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ste_WalterMRosebroughJr.Member" substitutionGroup="xbrli:item" />
  <element name="PriorPeerGroupTotalShareHolderReturn" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ste_PriorPeerGroupTotalShareHolderReturn" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="InsiderTradingPoliciesAndProceduresAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ste_InsiderTradingPoliciesAndProceduresAbstract" substitutionGroup="xbrli:item" />
  <element name="AwardTimingDisclosureAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ste_AwardTimingDisclosureAbstract" substitutionGroup="xbrli:item" />
</schema>
