Surname ธรรมรัตน (Thammarat 
, ธรรมรัตน ) , throughout the world, is quite a rare cognomen. The cognomen ธรรมรัตน is characteristic of Thailand, where it is quite a rare surname, Malaysia, where it is a rare surname, and Norway, where it is a very rare surname. Measured by absolute frequency, it is the most numerous in Thailand, Malaysia, and the United States. Likewise, ธรรมรัตน is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Thammarat | Malaysia, Norway, China, United States, Thailand |
| ธรรมรัตน | Thailand |