diff --git a/Gulpfile.ts b/Gulpfile.ts
index 054e99c8003..7072becc2da 100644
--- a/Gulpfile.ts
+++ b/Gulpfile.ts
@@ -330,6 +330,7 @@ const builtGeneratedDiagnosticMessagesJSON = path.join(builtLocalDirectory, "dia
 // processDiagnosticMessages script
 gulp.task(processDiagnosticMessagesJs, false, [], () => {
     const settings: tsc.Settings = getCompilerSettings({
+        target: "es5",
         declaration: false,
         removeComments: true,
         noResolve: false,