diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index 8d1700f8f..0c51da5f6 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -36,6 +36,11 @@ const ZOTERO_CONFIG = {
 	PREF_BRANCH: 'extensions.zotero.'
 };
 
+// Fx4.0b8+ use implicit SJOWs; no creation necessary
+if(!XPCSafeJSObjectWrapper) {
+	var XPCSafeJSObjectWrapper = function(arg) { return arg };
+}
+
 /*
  * Core functions
  */