Family name Promkhamsao (Promkhamsao 
) , in the world, is a very rare last name. The surname Promkhamsao is habitual in South-eastern Asia, particularly Thailand, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Promkhamsao | Thailand |
Pramuan, Nilnate, Narissara, and Pattharachon