diff --git a/packages/tre/src/http/websocket.ts b/packages/tre/src/http/websocket.ts
index 2f1ab39f7..572c89569 100644
--- a/packages/tre/src/http/websocket.ts
+++ b/packages/tre/src/http/websocket.ts
@@ -267,6 +267,8 @@ export async function coupleWebSocket(
   pair.addEventListener("close", (e) => {
     if (e.code === 1005 /* No Status Received */) {
       ws.close();
+    } else if (e.code === 1006 /* Abnormal Closure */) {
+      ws.terminate();
     } else {
       ws.close(e.code, e.reason);
     }
diff --git a/packages/tre/src/index.ts b/packages/tre/src/index.ts
index d6329701c..e1e700deb 100644
--- a/packages/tre/src/index.ts
+++ b/packages/tre/src/index.ts
@@ -240,7 +240,13 @@ export class Miniflare {
     this.#log.debug(`Running workerd ${desc}...`);
 
     this.#liveReloadServer = new WebSocketServer({ noServer: true });
-    this.#webSocketServer = new WebSocketServer({ noServer: true });
+    this.#webSocketServer = new WebSocketServer({
+      noServer: true,
+      // Disable automatic handling of `Sec-WebSocket-Protocol` header,
+      // Cloudflare Workers require users to include this header themselves in
+      // `Response`s: https://github.com/cloudflare/miniflare/issues/179
+      handleProtocols: () => false,
+    });
     // Add custom headers included in response to WebSocket upgrade requests
     this.#webSocketExtraHeaders = new WeakMap();
     this.#webSocketServer.on("headers", (headers, req) => {
diff --git a/packages/tre/test/index.spec.ts b/packages/tre/test/index.spec.ts
index 725504bd2..90a5511f9 100644
--- a/packages/tre/test/index.spec.ts
+++ b/packages/tre/test/index.spec.ts
@@ -23,7 +23,13 @@ test("Miniflare: web socket kitchen sink", async (t) => {
 
   // Create WebSocket origin server
   const server = http.createServer();
-  const wss = new WebSocketServer({ server });
+  const wss = new WebSocketServer({
+    server,
+    handleProtocols(protocols) {
+      t.deepEqual(protocols, new Set(["protocol1", "protocol2"]));
+      return "protocol2";
+    },
+  });
   wss.on("connection", (ws, req) => {
     // Testing receiving additional headers sent from upgrade request
     t.is(req.headers["user-agent"], "Test");
@@ -63,7 +69,11 @@ test("Miniflare: web socket kitchen sink", async (t) => {
 
   // Testing dispatchFetch WebSocket coupling
   const res = await mf.dispatchFetch("http://localhost", {
-    headers: { Upgrade: "websocket", "User-Agent": "Test" },
+    headers: {
+      Upgrade: "websocket",
+      "User-Agent": "Test",
+      "Sec-WebSocket-Protocol": "protocol1, protocol2",
+    },
     cf: { country: "MF" },
   });
 
@@ -74,6 +84,7 @@ test("Miniflare: web socket kitchen sink", async (t) => {
   res.webSocket.close(1000, "Test Closure");
   // Test receiving additional headers from upgrade response
   t.is(res.headers.get("Set-Cookie"), "key=value");
+  t.is(res.headers.get("Sec-WebSocket-Protocol"), "protocol2");
 
   // Check event results
   const clientEvent = await clientEventPromise;