Cognomen Promniwat (Promniwat 
) , globally, is a very rare family name. The last name Promniwat is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname.
| VARIANT | COUNTRY |
|---|---|
| Promniwat | Thailand |
Piyada, Kanokporn, Ratchaneekon, and Watcharapong