diff --git a/testing/web-platform/tests/interfaces/speech-api.idl b/testing/web-platform/tests/interfaces/speech-api.idl
index 563d64cd3b7c0..2ed9c2ce8b817 100644
--- a/testing/web-platform/tests/interfaces/speech-api.idl
+++ b/testing/web-platform/tests/interfaces/speech-api.idl
@@ -90,7 +90,7 @@ dictionary SpeechRecognitionEventInit : EventInit {
 };
 
 // The object representing a speech grammar
-[Exposed=Window, Constructor]
+[Exposed=Window]
 interface SpeechGrammar {
     attribute DOMString src;
     attribute float weight;