Cognomen 徐阶 (徐阶 
) , around the globe, is a very rare last name. The cognomen 徐阶 is habitual in Eastern Asia, particularly China, where it is an extremely rare surname. More prevalently, 徐阶 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| 徐阶 | China |