diff --git a/redash/models/base.py b/redash/models/base.py
index 461aa21a3d..529fff6329 100644
--- a/redash/models/base.py
+++ b/redash/models/base.py
@@ -18,6 +18,8 @@ def apply_pool_defaults(self, app, options):
         super(RedashSQLAlchemy, self).apply_pool_defaults(app, options)
         if settings.SQLALCHEMY_DISABLE_POOL:
             options['poolclass'] = NullPool
+            # Remove options NullPool does not support:
+            options.pop('max_overflow')
 
 
 db = RedashSQLAlchemy(session_options={