diff --git a/phpBB/includes/notification/type/bookmark.php b/phpBB/includes/notification/type/bookmark.php
index 4e48a967d0..946cb9b4ed 100644
--- a/phpBB/includes/notification/type/bookmark.php
+++ b/phpBB/includes/notification/type/bookmark.php
@@ -89,6 +89,7 @@ class phpbb_notification_type_bookmark extends phpbb_notification_type_post
 		{
 			return array();
 		}
+		sort($users);
 
 		$auth_read = $this->auth->acl_get_list($users, 'f_read', $post['forum_id']);