--- a/browser/components/enterprisepolicies/Policies.jsm
+++ b/browser/components/enterprisepolicies/Policies.jsm
@@ -36,16 +36,17 @@ this.Policies = {
       }
     }
   },
 
   "BlockAboutConfig": {
     onBeforeUIStartup(manager, param) {
       if (param) {
         manager.disallowFeature("about:config", true);
+        setAndLockPref("devtools.chrome.enabled", false);
       }
     }
   },
 
   "BlockAboutProfiles": {
     onBeforeUIStartup(manager, param) {
       if (param) {
         manager.disallowFeature("about:profiles", true);