diff --git a/qutebrowser/browser/greasemonkey.py b/qutebrowser/browser/greasemonkey.py
index a616891d1..41d32bcf1 100644
--- a/qutebrowser/browser/greasemonkey.py
+++ b/qutebrowser/browser/greasemonkey.py
@@ -201,7 +201,8 @@ unsafeWindow = window;
             scriptName=self.name,
             scriptInfo=self._meta_json(),
             scriptMeta=self.script_meta)
-        return '\n'.join([gm_bootstrap, self._code])
+        return '\n'.join(
+            ["(function(){", gm_bootstrap, self._code, "})();"])
 
     def _meta_json(self):
         return json.dumps({