diff --git a/vsintegration/src/FSharp.LanguageService/FSharp.LanguageService.fsproj b/vsintegration/src/FSharp.LanguageService/FSharp.LanguageService.fsproj
index 22c3f49cf78758c60afe417007864161ee5aa000..5ac5900f574beceba90b19d9afe0a4bed3c7ed04 100644
--- a/vsintegration/src/FSharp.LanguageService/FSharp.LanguageService.fsproj
+++ b/vsintegration/src/FSharp.LanguageService/FSharp.LanguageService.fsproj
@@ -67,6 +67,7 @@
       <GeneratedModuleName>Microsoft.VisualStudio.FSharp.LanguageService.Strings</GeneratedModuleName>
     </EmbeddedResource>
     <Compile Include="AssemblyInfo.fs" />
+    <Compile Include="LanguageServiceConstants.fs" />
     <Compile Include="Error.fs" />
     <Compile Include="Vs.fs" />
     <Compile Include="Colorize.fs" />
diff --git a/vsintegration/src/FSharp.LanguageService/LanguageServiceConstants.fs b/vsintegration/src/FSharp.LanguageService/LanguageServiceConstants.fs
new file mode 100644
index 0000000000000000000000000000000000000000..b64d0405948cd47549d6a303560cf83f24a6904c
--- /dev/null
+++ b/vsintegration/src/FSharp.LanguageService/LanguageServiceConstants.fs
@@ -0,0 +1,10 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
+
+namespace Microsoft.VisualStudio.FSharp.LanguageService
+
+[<RequireQualifiedAccess>]
+module internal LanguageServiceConstants =
+    
+    /// "F#"
+    [<Literal>]
+    let FSharpLanguageName = "F#"
diff --git a/vsintegration/src/FSharp.LanguageService/ProjectSitesAndFiles.fs b/vsintegration/src/FSharp.LanguageService/ProjectSitesAndFiles.fs
index 22ea0db010759d87c5f3845c2aeb8a91c0934da8..44d8a7b6d55180c46ad505134f1737774dba29dc 100644
--- a/vsintegration/src/FSharp.LanguageService/ProjectSitesAndFiles.fs
+++ b/vsintegration/src/FSharp.LanguageService/ProjectSitesAndFiles.fs
@@ -274,7 +274,7 @@ type internal ProjectSitesAndFiles() =
                         if not (isNull project) then
                             for reference in project.ProjectReferences do
                                 let project = workspace.CurrentSolution.GetProject(reference.ProjectId)
-                                if not (isNull project) then
+                                if not (isNull project) && (project.Language = LanguageServiceConstants.FSharpLanguageName) then
                                     let siteProvider = provideProjectSiteProvider (workspace, project, serviceProvider, projectOptionsTable)
                                     let referenceProject = workspace.ProjectTracker.GetProject(reference.ProjectId)
                                     let outputPath = referenceProject.BinOutputPath