diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 2c187e3358b..587c75f167b 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -5850,6 +5850,12 @@
             "url": "/_mozilla/mozilla/htmlspacechars.html"
           }
         ],
+        "mozilla/iframe-unblock-onload.html": [
+          {
+            "path": "mozilla/iframe-unblock-onload.html",
+            "url": "/_mozilla/mozilla/iframe-unblock-onload.html"
+          }
+        ],
         "mozilla/iframe_contentDocument.html": [
           {
             "path": "mozilla/iframe_contentDocument.html",
diff --git a/tests/wpt/mozilla/tests/mozilla/iframe-unblock-onload.html b/tests/wpt/mozilla/tests/mozilla/iframe-unblock-onload.html
new file mode 100644
index 00000000000..bc0ff4afcd7
--- /dev/null
+++ b/tests/wpt/mozilla/tests/mozilla/iframe-unblock-onload.html
@@ -0,0 +1,18 @@
+<html>
+<head>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<iframe src="resources/iframe_contentDocument_inner.html?pipe=trickle(d20)"></iframe>
+<script>
+  async_test(function(t) {
+    window.addEventListener('load', t.step_func(function() {
+      t.done();
+    }, false));
+
+    document.querySelector('iframe').remove();
+  }, "Document load is unblocked by iframe removal");
+</script>
+</body>
+</html>
