diff --git a/src/StringTools/StringTools.csproj b/src/StringTools/StringTools.csproj
index ccdba89ec9a..2f0f43eb5c7 100644
--- a/src/StringTools/StringTools.csproj
+++ b/src/StringTools/StringTools.csproj
@@ -14,6 +14,12 @@
 
     <AssemblyName>Microsoft.NET.StringTools</AssemblyName>
     <PackageDescription>This package contains the $(AssemblyName) assembly which implements common string-related functionality such as weak interning.</PackageDescription>
+    
+    <IncludeBuildOutput Condition="'$(TargetFramework)' == 'net35'">false</IncludeBuildOutput>
+    <!-- Don't publish the reference assembly if the build output isn't included. -->
+    <TargetsForTfmSpecificBuildOutput Condition="'$(IncludeBuildOutput)' == 'false'" />
+    <!-- NU5128: Add lib or ref assemblies for the net35 target framework. -->
+    <NoWarn>$(NoWarn);NU5128</NoWarn>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">