diff --git a/dom/base/ScriptSettings.cpp b/dom/base/ScriptSettings.cpp
index 53c3e23d3050..a8eb721f9923 100644
--- a/dom/base/ScriptSettings.cpp
+++ b/dom/base/ScriptSettings.cpp
@@ -851,28 +851,6 @@ AutoJSContext::operator JSContext*() const
   return mCx;
 }
 
-ThreadsafeAutoJSContext::ThreadsafeAutoJSContext(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_IN_IMPL)
-{
-  MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-
-  if (NS_IsMainThread()) {
-    mCx = nullptr;
-    mAutoJSContext.emplace();
-  } else {
-    mCx = mozilla::dom::workers::GetCurrentThreadJSContext();
-    mRequest.emplace(mCx);
-  }
-}
-
-ThreadsafeAutoJSContext::operator JSContext*() const
-{
-  if (mCx) {
-    return mCx;
-  } else {
-    return *mAutoJSContext;
-  }
-}
-
 AutoSafeJSContext::AutoSafeJSContext(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_IN_IMPL)
   : AutoJSAPI()
 {
diff --git a/dom/base/ScriptSettings.h b/dom/base/ScriptSettings.h
index 7506cf4014df..cb0e05a8a427 100644
--- a/dom/base/ScriptSettings.h
+++ b/dom/base/ScriptSettings.h
@@ -444,22 +444,6 @@ protected:
   MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 
-/**
- * Use ThreadsafeAutoJSContext when you want an AutoJSContext but might be
- * running on a worker thread.
- */
-class MOZ_RAII ThreadsafeAutoJSContext {
-public:
-  explicit ThreadsafeAutoJSContext(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM);
-  operator JSContext*() const;
-
-private:
-  JSContext* mCx; // Used on workers.  Null means mainthread.
-  Maybe<JSAutoRequest> mRequest; // Used on workers.
-  Maybe<AutoJSContext> mAutoJSContext; // Used on main thread.
-  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
-};
-
 /**
  * AutoSafeJSContext is similar to AutoJSContext but will only return the safe
  * JS context. That means it will never call nsContentUtils::GetCurrentJSContext().