diff --git a/tools/broccoli/broccoli-typescript.ts b/tools/broccoli/broccoli-typescript.ts
index 8410e4b5bd..aabd46af4e 100644
--- a/tools/broccoli/broccoli-typescript.ts
+++ b/tools/broccoli/broccoli-typescript.ts
@@ -128,7 +128,7 @@ class CustomLanguageServiceHost implements ts.LanguageServiceHost {
   constructor(private compilerOptions: ts.CompilerOptions, private fileNames: string[],
               private fileRegistry: FileRegistry, private treeInputPath: string) {
     this.currentDirectory = process.cwd();
-    this.defaultLibFilePath = ts.getDefaultLibFilePath(compilerOptions);
+    this.defaultLibFilePath = ts.getDefaultLibFilePath(compilerOptions).replace(/\\/g, '/');
   }