diff --git a/setup.cfg b/setup.cfg
index 03dc960d..0833c6f9 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -50,6 +50,7 @@ install_requires =
     sqlalchemy<2.0.0,>=1.4.0
 ; Keep in sync with extras dependency
     snowflake-connector-python<3.0.0
+    six>=1.4.0
 include_package_data = True
 package_dir =
     =src