Cognomen ธรรมธาตุ (Thammathat 
, Khammathat , ธรรมธาตุ ) , globally, is a rare family name. The cognomen ธรรมธาตุ is habitual in South-eastern Asia, particularly Thailand, where it is a rare surname. Also, ธรรมธาตุ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Khammathat, Thammathat, ธรรมธาตุ, Thamthatod | Thailand |
Thamathat, and Themmathat