diff --git a/tests/wpt/mozilla/meta/mozilla/worklets/__dir__.ini b/tests/wpt/mozilla/meta/mozilla/worklets/__dir__.ini
index 43043a1b6c3d..c000a50cb3b3 100644
--- a/tests/wpt/mozilla/meta/mozilla/worklets/__dir__.ini
+++ b/tests/wpt/mozilla/meta/mozilla/worklets/__dir__.ini
@@ -1 +1 @@
-prefs: [dom.worklet.enabled:true,dom.worklet.blockingsleep.enabled:true]
+prefs: [dom.worklet.enabled:true,dom.worklet.blockingsleep.enabled:true,dom.worklet.timeout_ms:5000]