diff --git a/src/libraries/oob-gen.proj b/src/libraries/oob-gen.proj
new file mode 100644
index 0000000000000..d565a1592a6ae
--- /dev/null
+++ b/src/libraries/oob-gen.proj
@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.Build.Traversal">
+
+  <!-- Reference all out-of-band generator projects. -->
+  <ItemGroup>
+    <ProjectReference Include="$(MSBuildThisFileDirectory)*\gen\**\*.*proj"
+                      Exclude="@(ProjectExclusions)" />
+  </ItemGroup>
+
+</Project>
diff --git a/src/libraries/oob.proj b/src/libraries/oob.proj
index d49efa6e61681..b94fb00dbd813 100644
--- a/src/libraries/oob.proj
+++ b/src/libraries/oob.proj
@@ -18,6 +18,7 @@
 
   <ItemGroup Condition="'$(BuildTargetFramework)' != '$(NetCoreAppCurrent)' or '$(BuildTargetFramework)' == ''">
     <ProjectReference Include="oob-all.proj" SkipGetTargetFrameworkProperties="true" />
+    <ProjectReference Include="oob-gen.proj" />
   </ItemGroup>
 
   <!-- Support building reference projects only. -->