diff --git a/dom/webidl/DedicatedWorkerGlobalScope.webidl b/dom/webidl/DedicatedWorkerGlobalScope.webidl
index 57b48839f70d..b9e9808c5e4a 100644
--- a/dom/webidl/DedicatedWorkerGlobalScope.webidl
+++ b/dom/webidl/DedicatedWorkerGlobalScope.webidl
@@ -19,7 +19,9 @@ interface DedicatedWorkerGlobalScope : WorkerGlobalScope {
   readonly attribute DOMString name;
 
   [Throws]
-  void postMessage(any message, optional sequence<object> transfer = []);
+  void postMessage(any message, sequence<object> transfer);
+  [Throws]
+  void postMessage(any message, optional PostMessageOptions options);
 
   void close();
 
diff --git a/dom/webidl/Worker.webidl b/dom/webidl/Worker.webidl
index d8ddccbca45f..c3786bb993b4 100644
--- a/dom/webidl/Worker.webidl
+++ b/dom/webidl/Worker.webidl
@@ -18,7 +18,9 @@ interface Worker : EventTarget {
   void terminate();
 
   [Throws]
-  void postMessage(any message, optional sequence<object> transfer = []);
+  void postMessage(any message, sequence<object> transfer);
+  [Throws]
+  void postMessage(any message, optional PostMessageOptions aOptions);
 
   attribute EventHandler onmessage;
   attribute EventHandler onmessageerror;
diff --git a/dom/workers/Worker.cpp b/dom/workers/Worker.cpp
index 0da7814a5ca2..d2730c2af1be 100644
--- a/dom/workers/Worker.cpp
+++ b/dom/workers/Worker.cpp
@@ -124,6 +124,14 @@ Worker::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
   }
 }
 
+void
+Worker::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+                    const PostMessageOptions& aOptions,
+                    ErrorResult& aRv)
+{
+  PostMessage(aCx, aMessage, aOptions.mTransfer, aRv);
+}
+
 void
 Worker::Terminate()
 {
diff --git a/dom/workers/Worker.h b/dom/workers/Worker.h
index c0badbe8b848..601d106f4dec 100644
--- a/dom/workers/Worker.h
+++ b/dom/workers/Worker.h
@@ -19,6 +19,7 @@
 namespace mozilla {
 namespace dom {
 
+struct PostMessageOptions;
 struct WorkerOptions;
 class WorkerPrivate;
 
@@ -43,6 +44,11 @@ public:
               const Sequence<JSObject*>& aTransferable,
               ErrorResult& aRv);
 
+  void
+  PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+              const PostMessageOptions& aOptions,
+              ErrorResult& aRv);
+
   void
   Terminate();
 
diff --git a/dom/workers/WorkerScope.cpp b/dom/workers/WorkerScope.cpp
index 977336fb0c63..165044348d3d 100644
--- a/dom/workers/WorkerScope.cpp
+++ b/dom/workers/WorkerScope.cpp
@@ -614,6 +614,16 @@ DedicatedWorkerGlobalScope::PostMessage(JSContext* aCx,
   mWorkerPrivate->PostMessageToParent(aCx, aMessage, aTransferable, aRv);
 }
 
+void
+DedicatedWorkerGlobalScope::PostMessage(JSContext* aCx,
+                                        JS::Handle<JS::Value> aMessage,
+                                        const PostMessageOptions& aOptions,
+                                        ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+  mWorkerPrivate->PostMessageToParent(aCx, aMessage, aOptions.mTransfer, aRv);
+}
+
 void
 DedicatedWorkerGlobalScope::Close()
 {
diff --git a/dom/workers/WorkerScope.h b/dom/workers/WorkerScope.h
index 42f60c5ed660..e8eb14f4e094 100644
--- a/dom/workers/WorkerScope.h
+++ b/dom/workers/WorkerScope.h
@@ -33,6 +33,7 @@ class Function;
 class IDBFactory;
 enum class ImageBitmapFormat : uint8_t;
 class Performance;
+struct PostMessageOptions;
 class Promise;
 class RequestOrUSVString;
 class WorkerLocation;
@@ -261,6 +262,10 @@ public:
   PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
               const Sequence<JSObject*>& aTransferable,
               ErrorResult& aRv);
+  void
+  PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+              const PostMessageOptions& aOptions,
+              ErrorResult& aRv);
 
   void
   Close();
diff --git a/testing/web-platform/meta/workers/interfaces/DedicatedWorkerGlobalScope/postMessage/second-argument-dictionary.html.ini b/testing/web-platform/meta/workers/interfaces/DedicatedWorkerGlobalScope/postMessage/second-argument-dictionary.html.ini
deleted file mode 100644
index 5b2ecd5ab47b..000000000000
--- a/testing/web-platform/meta/workers/interfaces/DedicatedWorkerGlobalScope/postMessage/second-argument-dictionary.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[second-argument-dictionary.html]
-  [Using dictionary as postMessage's second argument]
-    expected: FAIL
-