Surname แสงธรรมชัย (Sangthumchai 
, แสงธรรมชัย , Sangtumchai ) , across the world, is a rare last name. The cognomen แสงธรรมชัย is habitual in Thailand, where it is a rare surname, and the United States, where it is an extremely rare surname. Very seldom, แสงธรรมชัย is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sangthumchai | United States, Thailand |
| Sangthamchai, แสงธรรมชัย, Sangtumchai | Thailand |