diff --git a/browser/devtools/webconsole/test/browser_console_private_browsing.js b/browser/devtools/webconsole/test/browser_console_private_browsing.js
index 61cfd51c657..45e995ce5b8 100644
--- a/browser/devtools/webconsole/test/browser_console_private_browsing.js
+++ b/browser/devtools/webconsole/test/browser_console_private_browsing.js
@@ -15,6 +15,10 @@ function test()
   let privateWindow, privateBrowser, privateTab, privateContent;
   let hud, expectedMessages, nonPrivateMessage;
 
+  // This test is slightly more involved: it opens the web console twice,
+  // a new private window once, and the browser console twice. We can get
+  // a timeout with debug builds on slower machines.
+  requestLongerTimeout(2);
   start();
 
   function start()