Cognomen แจ่มใจ (Chaemchai 
, Chamjai 
, แจ่มใจ) , around the world, is a very rare family name. The surname แจ่มใจ is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname. Much less frequently, แจ่มใจ is the forename as well as the last name.