diff --git a/dom/script/ScriptLoader.cpp b/dom/script/ScriptLoader.cpp
index c2b692a71885..192322553c9e 100644
--- a/dom/script/ScriptLoader.cpp
+++ b/dom/script/ScriptLoader.cpp
@@ -1781,6 +1781,10 @@ ScriptLoader::FireScriptEvaluated(nsresult aResult,
 already_AddRefed<nsIScriptGlobalObject>
 ScriptLoader::GetScriptGlobalObject()
 {
+  if (!mDocument) {
+    return nullptr;
+  }
+
   nsPIDOMWindowInner* pwin = mDocument->GetInnerWindow();
   if (!pwin) {
     return nullptr;