--- a/devtools/client/netmonitor/test/browser_net_filter-01.js
+++ b/devtools/client/netmonitor/test/browser_net_filter-01.js
@@ -190,17 +190,17 @@ const EXPECTED_REQUESTS = [
       status: 200,
       statusText: "OK",
       type: "x-shockwave-flash",
       fullMimeType: "application/x-shockwave-flash",
     },
   },
   {
     method: "GET",
-    url: WS_CONTENT_TYPE_SJS + "?fmt=ws",
+    url: WS_WS_CONTENT_TYPE_SJS + "?fmt=ws",
     data: {
       fuzzyUrl: true,
       status: 101,
       statusText: "Switching Protocols",
     },
   },
 ];
 

--- a/devtools/client/netmonitor/test/browser_net_websocket_stacks.js
+++ b/devtools/client/netmonitor/test/browser_net_websocket_stacks.js
@@ -15,34 +15,34 @@ const EXPECTED_REQUESTS = [
     method: "GET",
     url: TOP_URL,
     causeType: "document",
     causeUri: null,
     stack: false,
   },
   {
     method: "GET",
-    url: "http://localhost:8080/",
+    url: "ws://localhost:8080/",
     causeType: "websocket",
     causeUri: TOP_URL,
     stack: [
       { fn: "openSocket", file: TOP_FILE_NAME, line: 6 },
       { file: TOP_FILE_NAME, line: 3 },
     ],
   },
   {
     method: "GET",
     url: EXAMPLE_URL + WORKER_FILE_NAME,
     causeType: "script",
     causeUri: TOP_URL,
     stack: [{ file: TOP_FILE_NAME, line: 9 }],
   },
   {
     method: "GET",
-    url: "https://localhost:8081/",
+    url: "wss://localhost:8081/",
     causeType: "websocket",
     causeUri: TOP_URL,
     stack: [
       { fn: "openWorkerSocket", file: WORKER_FILE_NAME, line: 5 },
       { file: WORKER_FILE_NAME, line: 2 },
     ],
   },
 ];

--- a/devtools/client/netmonitor/test/head.js
+++ b/devtools/client/netmonitor/test/head.js
@@ -95,16 +95,17 @@ const OPEN_REQUEST_IN_TAB_URL = EXAMPLE_
 const CSP_URL = EXAMPLE_URL + "html_csp-test-page.html";
 const CSP_RESEND_URL = EXAMPLE_URL + "html_csp-resend-test-page.html";
 
 const SIMPLE_SJS = EXAMPLE_URL + "sjs_simple-test-server.sjs";
 const SIMPLE_UNSORTED_COOKIES_SJS =
   EXAMPLE_URL + "sjs_simple-unsorted-cookies-test-server.sjs";
 const CONTENT_TYPE_SJS = EXAMPLE_URL + "sjs_content-type-test-server.sjs";
 const WS_CONTENT_TYPE_SJS = WS_HTTP_URL + "sjs_content-type-test-server.sjs";
+const WS_WS_CONTENT_TYPE_SJS = WS_URL + "sjs_content-type-test-server.sjs";
 const HTTPS_CONTENT_TYPE_SJS =
   HTTPS_EXAMPLE_URL + "sjs_content-type-test-server.sjs";
 const SERVER_TIMINGS_TYPE_SJS =
   HTTPS_EXAMPLE_URL + "sjs_timings-test-server.sjs";
 const STATUS_CODES_SJS = EXAMPLE_URL + "sjs_status-codes-test-server.sjs";
 const SORTING_SJS = EXAMPLE_URL + "sjs_sorting-test-server.sjs";
 const HTTPS_REDIRECT_SJS = EXAMPLE_URL + "sjs_https-redirect-test-server.sjs";
 const CORS_SJS_PATH =

--- a/devtools/server/actors/network-monitor/network-observer.js
+++ b/devtools/server/actors/network-monitor/network-observer.js
@@ -680,16 +680,31 @@ NetworkObserver.prototype = {
     if (channel.loadInfo) {
       causeType = channel.loadInfo.externalContentPolicyType;
       const { loadingPrincipal } = channel.loadInfo;
       if (loadingPrincipal && loadingPrincipal.URI) {
         causeUri = loadingPrincipal.URI.spec;
       }
     }
 
+    // Show the right WebSocket URL in case of WS channel.
+    if (channel.notificationCallbacks) {
+      let wsChannel = null;
+      try {
+        wsChannel = channel.notificationCallbacks.QueryInterface(
+          Ci.nsIWebSocketChannel
+        );
+      } catch (e) {
+        // Not all channels implement nsIWebSocketChannel.
+      }
+      if (wsChannel) {
+        event.url = wsChannel.URI.spec;
+      }
+    }
+
     event.cause = {
       type: causeTypeToString(causeType),
       loadingDocumentUri: causeUri,
       stacktrace,
     };
 
     httpActivity.isXHR = event.isXHR =
       causeType === Ci.nsIContentPolicy.TYPE_XMLHTTPREQUEST ||