diff --git a/rhodecode/lib/hooks.py b/rhodecode/lib/hooks.py
--- a/rhodecode/lib/hooks.py
+++ b/rhodecode/lib/hooks.py
@@ -34,7 +34,7 @@ from rhodecode.lib import helpers as h
 from rhodecode.lib.utils import action_logger
 from rhodecode.lib.vcs.backends.base import EmptyChangeset
 from rhodecode.lib.compat import json
-from rhodecode.lib.exceptions import HTTPLockedRC
+from rhodecode.lib.exceptions import HTTPLockedRC, UserCreationError
 from rhodecode.lib.utils2 import safe_str, _extract_extras
 from rhodecode.model.db import Repository, User
 
@@ -252,6 +252,15 @@ def log_create_repository(repository_dic
     return 0
 
 
+def check_allowed_create_user(user_dict, created_by, **kwargs):
+    from rhodecode import EXTENSIONS
+    callback = getattr(EXTENSIONS, 'PRE_CREATE_USER_HOOK', None)
+    if isfunction(callback):
+        allowed, reason = callback(created_by=created_by, **user_dict)
+        if not allowed:
+            raise UserCreationError(reason)
+
+
 def log_create_user(user_dict, created_by, **kwargs):
     """
     Post create user Hook. This is a dummy function for admins to re-use