Family name Cảo (Као 
, Cảo 
) , globally, is a rare last name. The cognomen Cảo is characteristic of Eastern Europe, particularly Belarus, where it is a rare surname, Russia, and Ukraine. Much less frequently, Cảo is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Као | Kazakhstan, Russia, Kyrgyzstan, Belarus, Ukraine |
| Cảo | Vietnam |
| bùi quý cảo VN (b. 1923) |
|