Family name แจ้งใจ (Jangjai 
, แจ้งใจ, Jaengjai ) , in all the world, is a rare last name. The surname แจ้งใจ is habitual in Thailand, where it is a rare surname, and the United States, where it is an extremely rare surname. Very seldom, แจ้งใจ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Jangjai | United States, India, Thailand |
| Chaengchai, Jaengjai | Thailand |
Chaengjai, Jaenjai, and Jangchadjai