diff --git a/ext/broadcast_channel/01_broadcast_channel.js b/ext/broadcast_channel/01_broadcast_channel.js
index d92aef0728..ab315eaa6e 100644
--- a/ext/broadcast_channel/01_broadcast_channel.js
+++ b/ext/broadcast_channel/01_broadcast_channel.js
@@ -8,6 +8,7 @@ import * as webidl from "ext:deno_webidl/00_webidl.js";
 import {
   defineEventHandler,
   EventTarget,
+  setIsTrusted,
   setTarget,
 } from "ext:deno_web/02_event.js";
 import DOMException from "ext:deno_web/01_dom_exception.js";
@@ -56,6 +57,7 @@ function dispatch(source, name, data) {
         data: core.deserialize(data), // TODO(bnoordhuis) Cache immutables.
         origin: "http://127.0.0.1",
       });
+      setIsTrusted(event, true);
       setTarget(event, channel);
       channel.dispatchEvent(event);
     };
diff --git a/ext/web/13_message_port.js b/ext/web/13_message_port.js
index 08f668b2de..40145db784 100644
--- a/ext/web/13_message_port.js
+++ b/ext/web/13_message_port.js
@@ -14,6 +14,7 @@ import {
   EventTarget,
   MessageEvent,
   setEventTargetData,
+  setIsTrusted,
 } from "ext:deno_web/02_event.js";
 import DOMException from "ext:deno_web/01_dom_exception.js";
 const primordials = globalThis.__bootstrap.primordials;
@@ -155,6 +156,7 @@ class MessagePort extends EventTarget {
           transferables = v[1];
         } catch (err) {
           const event = new MessageEvent("messageerror", { data: err });
+          setIsTrusted(event, true);
           this.dispatchEvent(event);
           return;
         }
@@ -165,6 +167,7 @@ class MessagePort extends EventTarget {
             (t) => ObjectPrototypeIsPrototypeOf(MessagePortPrototype, t),
           ),
         });
+        setIsTrusted(event, true);
         this.dispatchEvent(event);
       }
       this[_enabled] = false;
diff --git a/ext/websocket/01_websocket.js b/ext/websocket/01_websocket.js
index 3f4e16b909..71abb08303 100644
--- a/ext/websocket/01_websocket.js
+++ b/ext/websocket/01_websocket.js
@@ -17,6 +17,7 @@ import {
   Event,
   EventTarget,
   MessageEvent,
+  setIsTrusted,
 } from "ext:deno_web/02_event.js";
 import { Blob, BlobPrototype } from "ext:deno_web/09_file.js";
 import { getLocationHref } from "ext:deno_web/12_location.js";
@@ -430,6 +431,7 @@ class WebSocket extends EventTarget {
             data: op_ws_get_buffer_as_string(rid),
             origin: this[_url],
           });
+          setIsTrusted(event, true);
           dispatch(this, event);
           break;
         }
@@ -450,6 +452,7 @@ class WebSocket extends EventTarget {
             origin: this[_url],
             [_skipInternalInit]: true,
           });
+          setIsTrusted(event, true);
           dispatch(this, event);
           break;
         }
diff --git a/runtime/js/11_workers.js b/runtime/js/11_workers.js
index e046900053..f5548d8d12 100644
--- a/runtime/js/11_workers.js
+++ b/runtime/js/11_workers.js
@@ -22,6 +22,7 @@ import {
   ErrorEvent,
   EventTarget,
   MessageEvent,
+  setIsTrusted,
 } from "ext:deno_web/02_event.js";
 import {
   deserializeJsMessageData,
@@ -187,6 +188,7 @@ class Worker extends EventTarget {
           cancelable: false,
           data: err,
         });
+        setIsTrusted(event, true);
         this.dispatchEvent(event);
         return;
       }
@@ -198,6 +200,7 @@ class Worker extends EventTarget {
           (t) => ObjectPrototypeIsPrototypeOf(MessagePortPrototype, t),
         ),
       });
+      setIsTrusted(event, true);
       this.dispatchEvent(event);
     }
   };
diff --git a/runtime/js/99_main.js b/runtime/js/99_main.js
index 483ca9012c..dc68396469 100644
--- a/runtime/js/99_main.js
+++ b/runtime/js/99_main.js
@@ -154,6 +154,7 @@ async function pollForMessages() {
           ObjectPrototypeIsPrototypeOf(messagePort.MessagePortPrototype, t),
       ),
     });
+    event.setIsTrusted(msgEvent, true);
 
     try {
       globalDispatchEvent(msgEvent);
@@ -167,6 +168,7 @@ async function pollForMessages() {
         error: e,
       });
 
+      event.setIsTrusted(errorEvent, true);
       globalDispatchEvent(errorEvent);
       if (!errorEvent.defaultPrevented) {
         throw e;
diff --git a/tools/wpt/expectation.json b/tools/wpt/expectation.json
index 946f374ebe..19075e2244 100644
--- a/tools/wpt/expectation.json
+++ b/tools/wpt/expectation.json
@@ -6399,8 +6399,8 @@
     "Channel_postMessage_with_transfer_incoming_messages.any.worker.html": true,
     "Channel_postMessage_with_transfer_outgoing_messages.any.html": true,
     "Channel_postMessage_with_transfer_outgoing_messages.any.worker.html": true,
-    "MessageEvent-trusted.any.html": false,
-    "MessageEvent-trusted.any.worker.html": false,
+    "MessageEvent-trusted.any.html": true,
+    "MessageEvent-trusted.any.worker.html": true,
     "MessageEvent-trusted.window.html": false,
     "MessageEvent.any.html": true,
     "MessageEvent.any.worker.html": true,
@@ -9688,4 +9688,4 @@
       "media-sniff.window.html": false
     }
   }
-}
\ No newline at end of file
+}