Surname สมเย็น (สมเย็น 
) , around the globe, is a rare last name. The surname สมเย็น is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname. Much less frequently, สมเย็น is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| สมเย็น | Thailand |