--- a/mobile/android/gradle.configure
+++ b/mobile/android/gradle.configure
@@ -1,25 +1,29 @@
 # -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
 # vim: set filetype=python:
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 # If --with-gradle is specified, build mobile/android with Gradle.  If no
-# Gradle binary is specified, or if --without-gradle is specified, use the in
-# tree Gradle wrapper.  The wrapper downloads and installs Gradle, which is
-# good for local developers but not good in automation.
+# Gradle binary is specified use the in tree Gradle wrapper.  The wrapper
+# downloads and installs Gradle, which is good for local developers but not
+# good in automation.
 option('--with-gradle', nargs='?',
        default=True,
        help='Enable building mobile/android with Gradle '
             '(argument: location of binary or wrapper (gradle/gradlew))')
 
 @depends('--with-gradle')
 def with_gradle(value):
+    if not value:
+        die('Building --without-gradle is no longer supported: '
+            'see https://bugzilla.mozilla.org/show_bug.cgi?id=1414415.')
+
     if value:
         return True
 
 set_config('MOZ_BUILD_MOBILE_ANDROID_WITH_GRADLE', with_gradle)
 
 
 @depends('--with-gradle', check_build_environment)
 @imports(_from='os.path', _import='isfile')