--- a/dom/xhr/XMLHttpRequestWorker.cpp
+++ b/dom/xhr/XMLHttpRequestWorker.cpp
@@ -1008,27 +1008,31 @@ Proxy::HandleEvent(Event* aEvent)
     if (!GetOrCreateDOMReflectorNoWrap(cx, mXHR, &value)) {
       return NS_ERROR_FAILURE;
     }
 
     JS::Rooted<JSObject*> scope(cx, &value.toObject());
 
     RefPtr<EventRunnable> runnable;
     if (progressEvent) {
-      runnable = new EventRunnable(this, isUploadTarget, type,
-                                   progressEvent->LengthComputable(),
-                                   progressEvent->Loaded(),
-                                   progressEvent->Total(),
-                                   scope);
+      if (!mIsSyncXHR || !type.EqualsASCII(sEventStrings[STRING_progress])) {
+        runnable = new EventRunnable(this, isUploadTarget, type,
+                                     progressEvent->LengthComputable(),
+                                     progressEvent->Loaded(),
+                                     progressEvent->Total(),
+                                     scope);
+      }
     }
     else {
       runnable = new EventRunnable(this, isUploadTarget, type, scope);
     }
 
-    runnable->Dispatch();
+    if (runnable) {
+      runnable->Dispatch();
+    }
   }
 
   if (!isUploadTarget) {
     if (type.EqualsASCII(sEventStrings[STRING_loadstart])) {
       mMainThreadSeenLoadStart = true;
     }
     else if (mMainThreadSeenLoadStart &&
              type.EqualsASCII(sEventStrings[STRING_loadend])) {
@@ -1736,16 +1740,21 @@ XMLHttpRequestWorker::DispatchPrematureA
   }
 
   RefPtr<Event> event;
   if (aEventType.EqualsLiteral("readystatechange")) {
     event = NS_NewDOMEvent(aTarget, nullptr, nullptr);
     event->InitEvent(aEventType, false, false);
   }
   else {
+    if (mProxy->mIsSyncXHR &&
+        aEventType.EqualsASCII(sEventStrings[STRING_progress])) {
+      return;
+    }
+
     ProgressEventInit init;
     init.mBubbles = false;
     init.mCancelable = false;
     if (aUploadTarget) {
       init.mLengthComputable = mProxy->mLastUploadLengthComputable;
       init.mLoaded = mProxy->mLastUploadLoaded;
       init.mTotal = mProxy->mLastUploadTotal;
     }

deleted file mode 100644
--- a/testing/web-platform/meta/xhr/sync-no-progress.any.js.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[sync-no-progress.any.worker.html]
-  [progress event should not be fired by sync XHR]
-    expected: FAIL
-