Family name แจ่มจันทร์ (Jamjan 
, Jamjun , Chamchan , and others...) , across the world, is a rare surname. The surname แจ่มจันทร์ is characteristic of Thailand, where it is quite a rare surname, Malaysia, where it is a very rare surname, and the United States, where it is an extremely rare surname. Also, แจ่มจันทร์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Jamjan | South Africa, Malaysia, United States, Thailand, India |
| Chamchan, Jamjun | India, United States, Thailand |
| Chaemchan | Thailand |
| Jamchan | India, Thailand |
Chaeamchan, Chaemchang, Chaemchans, Chaemchantha, Chaemjan, Chaemmankhong, Chaewchamnan, Chaewchan, Jaemchan, Jaemchanta, Jaemjanras, and Jaenarn