--- a/testing/web-platform/meta/MANIFEST.json
+++ b/testing/web-platform/meta/MANIFEST.json
@@ -394432,17 +394432,19 @@
     [
      "/webdriver/tests/close_window/close.py",
      {}
     ]
    ],
    "webdriver/tests/close_window/user_prompts.py": [
     [
      "/webdriver/tests/close_window/user_prompts.py",
-     {}
+     {
+      "timeout": "long"
+     }
     ]
    ],
    "webdriver/tests/contexts/json_serialize_windowproxy.py": [
     [
      "/webdriver/tests/contexts/json_serialize_windowproxy.py",
      {
       "timeout": "long"
      }

--- a/testing/web-platform/tests/webdriver/tests/close_window/user_prompts.py
+++ b/testing/web-platform/tests/webdriver/tests/close_window/user_prompts.py
@@ -1,8 +1,10 @@
+# META: timeout=long
+
 from tests.support.asserts import assert_error, assert_dialog_handled
 from tests.support.fixtures import create_dialog, create_window
 from tests.support.inline import inline
 
 
 def close(session):
     return session.transport.send("DELETE", "session/%s/window" % session.session_id)