Cognomen สุมาทย์ (สุมาทย์ 
) , in the world, is an extremely rare family name. The surname สุมาทย์ is habitual in South-eastern Asia, particularly Thailand, where it is an extremely rare surname. Much less frequently, สุมาทย์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| สุมาทย์ | Thailand |