diff --git a/dom/xbl/nsXBLBinding.cpp b/dom/xbl/nsXBLBinding.cpp
index 76ad62d2b55e..1825d49091cf 100644
--- a/dom/xbl/nsXBLBinding.cpp
+++ b/dom/xbl/nsXBLBinding.cpp
@@ -965,7 +965,7 @@ nsXBLBinding::DoInitJSClass(JSContext *cx,
   JS::Rooted<JSObject*> parent_proto(cx);
   {
     JS::RootedObject wrapped(cx, obj);
-    JSAutoCompartment ac(cx, xblScope);
+    JSAutoRealm ar(cx, xblScope);
     if (!JS_WrapObject(cx, &wrapped)) {
       return NS_ERROR_FAILURE;
     }