diff --git a/src/tools/illink/src/ILLink.Tasks/build/Microsoft.NET.ILLink.targets b/src/tools/illink/src/ILLink.Tasks/build/Microsoft.NET.ILLink.targets
index af0ac935ad9f9..31656772b5ad3 100644
--- a/src/tools/illink/src/ILLink.Tasks/build/Microsoft.NET.ILLink.targets
+++ b/src/tools/illink/src/ILLink.Tasks/build/Microsoft.NET.ILLink.targets
@@ -192,6 +192,10 @@ Copyright (c) .NET Foundation. All rights reserved.
          is a NativeAOT app, value of SelfContained doesn't matter. -->
     <NETSdkError Condition="'$(RunILLink)' != 'false' And '$(SelfContained)' != 'true'" ResourceName="ILLinkNotSupportedError" />
 
+    <!-- Using a version of ILLink that doesn't match the target framework is not supported. -->
+    <Warning Condition="'$(SuppressILLinkTargetFrameworkVersionWarning)' != 'true' And '$(TargetFramework)' != 'net8.0'"
+             Text="Unsupported TargetFramework. This version of ILLink.Tasks only supports net8.0." />
+
     <PropertyGroup Condition=" '$(ILLinkWarningLevel)' == '' ">
       <ILLinkWarningLevel Condition=" '$(EffectiveAnalysisLevel)' != '' And
                                        $([MSBuild]::VersionGreaterThanOrEquals($(EffectiveAnalysisLevel), '5.0')) ">5</ILLinkWarningLevel>