--- a/dom/media/webspeech/synth/cocoa/OSXSpeechSynthesizerService.mm
+++ b/dom/media/webspeech/synth/cocoa/OSXSpeechSynthesizerService.mm
@@ -364,16 +364,24 @@ OSXSpeechSynthesizerService::Speak(const
                                    float aPitch,
                                    nsISpeechTask* aTask)
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
 
   MOZ_ASSERT(StringBeginsWith(aUri, NS_LITERAL_STRING("urn:moz-tts:osx:")),
              "OSXSpeechSynthesizerService doesn't allow this voice URI");
 
+  if (aText.IsEmpty()) {
+    // NSSpeechSynthesizer throws error when text is empty.
+    // If so, we dispatch start and end event instead of error
+    aTask->DispatchStart();
+    aTask->DispatchEnd(0, 0);
+    return NS_OK;
+  }
+
   NSSpeechSynthesizer* synth = [[NSSpeechSynthesizer alloc] init];
   // strlen("urn:moz-tts:osx:") == 16
   NSString* identifier = nsCocoaUtils::ToNSString(Substring(aUri, 16));
   [synth setVoice:identifier];
 
   // default rate is 180-220
   [synth setObject:[NSNumber numberWithInt:aRate * 200]
          forProperty:NSSpeechRateProperty error:nil];