diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index cbf9f4475d1..ce1b39b6720 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1243,6 +1243,7 @@ function system_library_info() {
       array('system', 'jquery'),
       array('system', 'drupal'),
       array('system', 'drupalSettings'),
+      array('system', 'drupal.ajax'),
       array('system', 'drupal.progress'),
       array('system', 'jquery.once'),
     ),