diff --git a/lib/6to5/file.js b/lib/6to5/file.js
index 64d2f7aad0..23adb84386 100644
--- a/lib/6to5/file.js
+++ b/lib/6to5/file.js
@@ -70,7 +70,12 @@ File.validOptions = [
   "ast",
   "format",
   "playground",
-  "experimental"
+  "experimental",
+
+  // these are used by plugins
+  "ignore",
+  "only",
+  "extensions"
 ];
 
 File.normaliseOptions = function (opts) {