Surname วันจันทร์ (Mond 
, วันจันทร์ 
, Wanchan 
) , across the world, is quite a common cognomen. The cognomen วันจันทร์ is characteristic of Luxembourg, where it is quite a rare surname, Myanmar, and Papua New Guinea. Measured by absolute frequency, the name is most common in South-eastern Asia, particularly Myanmar, Thailand, and Indonesia. Also, วันจันทร์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Mond | Germany, Malaysia, Indonesia, United States, Myanmar |
| วันจันทร์ | Thailand |
| Wanchan | Thailand, Malaysia, China, United States, India |
| Wanjan | Malaysia, India, Thailand, United States |