diff --git a/tests/wpt/mozilla/tests/mozilla/interfaces.html b/tests/wpt/mozilla/tests/mozilla/interfaces.html
index 8bbde3b46a8..9d262c595c6 100644
--- a/tests/wpt/mozilla/tests/mozilla/interfaces.html
+++ b/tests/wpt/mozilla/tests/mozilla/interfaces.html
@@ -189,6 +189,7 @@ test_interfaces([
   "PopStateEvent",
   "ProcessingInstruction",
   "ProgressEvent",
+  "PromiseRejectionEvent",
   "RadioNodeList",
   "Range",
   "Request",
diff --git a/tests/wpt/mozilla/tests/mozilla/interfaces.worker.js b/tests/wpt/mozilla/tests/mozilla/interfaces.worker.js
index 926ae2e1792..fbd6e92c097 100644
--- a/tests/wpt/mozilla/tests/mozilla/interfaces.worker.js
+++ b/tests/wpt/mozilla/tests/mozilla/interfaces.worker.js
@@ -40,6 +40,7 @@ test_interfaces([
   "PerformanceObserverEntryList",
   "PerformancePaintTiming",
   "ProgressEvent",
+  "PromiseRejectionEvent",
   "Request",
   "Response",
   "TextDecoder",