diff --git a/library/Icinga/Authentication/UserGroup/DbUserGroupBackend.php b/library/Icinga/Authentication/UserGroup/DbUserGroupBackend.php
index 5596f18b6..6f5c2e9dd 100644
--- a/library/Icinga/Authentication/UserGroup/DbUserGroupBackend.php
+++ b/library/Icinga/Authentication/UserGroup/DbUserGroupBackend.php
@@ -250,7 +250,7 @@ class DbUserGroupBackend extends DbRepository implements UserGroupBackendInterfa
      */
     protected function joinGroupMembership(RepositoryQuery $query)
     {
-        $query->getQuery()->join(
+        $query->getQuery()->joinLeft(
             $this->requireTable('group_membership'),
             'g.id = gm.group_id',
             array()