diff --git a/firebase_admin/_user_mgt.py b/firebase_admin/_user_mgt.py
index e65eb0fd5..cc5b75231 100644
--- a/firebase_admin/_user_mgt.py
+++ b/firebase_admin/_user_mgt.py
@@ -320,7 +320,7 @@ def delete_user(self, uid):
         """Deletes the user identified by the specified user ID."""
         _Validator.validate_uid(uid)
         try:
-            response = self._request('post', 'deleteAccount', json={'localId' : [uid]})
+            response = self._request('post', 'deleteAccount', json={'localId' : uid})
         except requests.exceptions.RequestException as error:
             self._handle_http_error(
                 USER_DELETE_ERROR, 'Failed to delete user: {0}.'.format(uid), error)