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 @@
Microsoft.VisualStudio.FSharp.LanguageService.Strings
+
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
+
+[]
+module internal LanguageServiceConstants =
+
+ /// "F#"
+ []
+ 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