diff --git a/build/zip.py b/build/zip.py
index 5e72d87f6060b..d1a283e69f2da 100644
--- a/build/zip.py
+++ b/build/zip.py
@@ -5,7 +5,9 @@
 import zipfile
 
 EXTENSIONS_TO_SKIP = [
-  '.pdb'
+  '.pdb',
+  '.mojom.js',
+  '.mojom-lite.js',
 ]
 
 PATHS_TO_SKIP = [