Last name Keophaythoun (Keophaythoun 
) , all around the world, is a rare family name. The cognomen Keophaythoun is habitual in South-eastern Asia, particularly Laos, where it is quite a rare surname, and Thailand, where it is an extremely rare surname.
| VARIANT | COUNTRY |
|---|---|
| Keophaythoun | Laos, Thailand |