diff --git a/data/model/user.py b/data/model/user.py
index 24c5b0ede..3ca44f9f5 100644
--- a/data/model/user.py
+++ b/data/model/user.py
@@ -583,7 +583,7 @@ def get_matching_users(username_prefix, robot_namespace=None, organization=None,
 
   query = (User
            .select(User.id, User.username, User.email, User.robot)
-           .group_by(User.username, User.email, User.robot)
+           .group_by(User.id, User.username, User.email, User.robot)
            .where(direct_user_query))
 
   if organization: