Surname Onnak (Onnak 
) , in the entire world, is a very rare last name. The surname Onnak is habitual in South-eastern Asia, particularly Thailand, where it is a very rare surname, and Philippines, where it is an extremely rare surname. Very seldom, Onnak is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Onnak | Thailand, India, Philippines |