diff --git a/lib/jsdom/browser/Window.js b/lib/jsdom/browser/Window.js
index 910092001d..c6039174c8 100644
--- a/lib/jsdom/browser/Window.js
+++ b/lib/jsdom/browser/Window.js
@@ -441,7 +441,10 @@ function Window(options) {
       return customElementRegistry;
     },
     get event() {
-      return idlUtils.wrapperForImpl(window._currentEvent);
+      return window._currentEvent ? idlUtils.wrapperForImpl(window._currentEvent) : undefined;
+    },
+    set event(value) {
+      Object.defineProperty(window, "event", { configurable: true, enumerable: true, writable: true, value });
     }
   });
 
diff --git a/test/web-platform-tests/to-run.yaml b/test/web-platform-tests/to-run.yaml
index f5e0a6ddb8..ea7d06f285 100644
--- a/test/web-platform-tests/to-run.yaml
+++ b/test/web-platform-tests/to-run.yaml
@@ -164,8 +164,7 @@ EventListener-incumbent-global-1.sub.html: [timeout, Multi-globals]
 EventListener-incumbent-global-2.sub.html: [timeout, Multi-globals]
 EventListener-invoke-legacy.html: [timeout, Animation stuff not implemented]
 EventTarget-dispatchEvent.html: [fail, We don't support every event interface yet]
-event-global-extra.window.html: [timeout, Not implemented]
-event-global.html: [fail, Not implemented]
+event-global-extra.window.html: [fail, We're supposed to check the event listener's global (not the Event's global)]
 relatedTarget.window.html: [fail, Unknown]
 webkit-animation-end-event.html: [fail, WebKit-prefixed events not implemented]
 webkit-animation-iteration-event.html: [fail, WebKit-prefixed events not implemented]
diff --git a/test/web-platform-tests/to-upstream/dom/events/event-global-replaceable.html b/test/web-platform-tests/to-upstream/dom/events/event-global-replaceable.html
new file mode 100644
index 0000000000..5fe48bcad2
--- /dev/null
+++ b/test/web-platform-tests/to-upstream/dom/events/event-global-replaceable.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>window.event is [Replaceable]</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+"use strict";
+
+test(() => {
+  window.event = "foo";
+
+  assert_equals(window.event, "foo");
+}, "Setting window.event replaces it");
+
+test(() => {
+  const target = document.createElement("div");
+  assert_equals(window.event, "foo", "Still set before dispatch");
+
+  const clickEvent = new Event("click");
+  let fired = false;
+  target.addEventListener("click", () => {
+    assert_equals(window.event, "foo", "Still set during dispatch");
+    fired = true;
+  });
+
+  target.dispatchEvent(clickEvent);
+  assert_equals(window.event, "foo", "still set after dispatch");
+  assert_true(fired);
+}, "Dispatching does not affect window.event after it's been replaced");
+</script>
