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