--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -1284,17 +1284,21 @@ pref("browser.newtabpage.rows", 3);
 pref("browser.newtabpage.columns", 5);
 
 // directory tiles download URL
 pref("browser.newtabpage.directory.source", "https://tiles.services.mozilla.com/v3/links/fetch/%LOCALE%/%CHANNEL%");
 
 // Activity Stream prefs that control to which page to redirect
 pref("browser.newtabpage.activity-stream.prerender", true);
 #ifndef RELEASE_OR_BETA
+#ifdef MOZILLA_OFFICIAL
 pref("browser.newtabpage.activity-stream.debug", false);
+#else
+pref("browser.newtabpage.activity-stream.debug", true);
+#endif
 #endif
 
 pref("browser.library.activity-stream.enabled", true);
 
 // Enable the DOM fullscreen API.
 pref("full-screen-api.enabled", true);
 
 // Startup Crash Tracking

--- a/browser/components/newtab/tests/xpcshell/test_AboutNewTabService.js
+++ b/browser/components/newtab/tests/xpcshell/test_AboutNewTabService.js
@@ -7,17 +7,17 @@
 ChromeUtils.import("resource://gre/modules/Services.jsm");
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
 ChromeUtils.import("resource://gre/modules/Preferences.jsm");
 ChromeUtils.import("resource://gre/modules/AppConstants.jsm");
 XPCOMUtils.defineLazyServiceGetter(this, "aboutNewTabService",
                                    "@mozilla.org/browser/aboutnewtab-service;1",
                                    "nsIAboutNewTabService");
 
-const IS_RELEASE_OR_BETA = AppConstants.RELEASE_OR_BETA;
+const {IS_RELEASE_OR_BETA, MOZILLA_OFFICIAL} = AppConstants;
 
 const ACTIVITY_STREAM_PRERENDER_URL = "resource://activity-stream/prerendered/en-US/activity-stream-prerendered.html";
 const ACTIVITY_STREAM_PRERENDER_DEBUG_URL = "resource://activity-stream/prerendered/static/activity-stream-prerendered-debug.html";
 const ACTIVITY_STREAM_URL = "resource://activity-stream/prerendered/en-US/activity-stream.html";
 const ACTIVITY_STREAM_DEBUG_URL = "resource://activity-stream/prerendered/static/activity-stream-debug.html";
 
 const DOWNLOADS_URL = "chrome://browser/content/downloads/contentAreaDownloadsView.xul";
 const ACTIVITY_STREAM_PRERENDER_PREF = "browser.newtabpage.activity-stream.prerender";
@@ -129,16 +129,26 @@ add_task(async function test_default_url
   cleanup();
 });
 
 add_task(function test_locale() {
   Assert.equal(aboutNewTabService.activityStreamLocale, "en-US",
     "The locale for testing should be en-US");
 });
 
+add_task(async function test_debug_mode() {
+  if (!IS_RELEASE_OR_BETA && !MOZILLA_OFFICIAL) { // Check if local build
+    Assert.equal(aboutNewTabService.activityStreamDebug, true,
+      "Debug mode is set for builds that are not official");
+  } else {
+    Assert.equal(aboutNewTabService.activityStreamDebug, false,
+      "Debug mode is not set for any other builds");
+  }
+});
+
 /**
  * Tests reponse to updates to prefs
  */
 add_task(async function test_updates() {
   /*
    * Simulates a "cold-boot" situation, with some pref already set before testing a series
    * of changes.
    */
@@ -190,16 +200,19 @@ function setBoolPrefAndWaitForChange(pre
     }, "newtab-url-changed");
 
     Services.prefs.setBoolPref(pref, value);
   });
 }
 
 
 function setupASPrerendered() {
+  // Don't run in debug mode regardless of build type
+  Services.prefs.setBoolPref(ACTIVITY_STREAM_DEBUG_PREF, false);
+
   if (Services.prefs.getBoolPref(ACTIVITY_STREAM_PRERENDER_PREF)) {
     return Promise.resolve();
   }
 
   let notificationPromise = nextChangeNotificationPromise("about:newtab");
   Services.prefs.setBoolPref(ACTIVITY_STREAM_PRERENDER_PREF, true);
   return notificationPromise;
 }