Surname ธารรัตน์ (ธารรัตน์ 
, Thanrat 
, Tarnrat ) , across the world, is a very rare last name. The family name ธารรัตน์ is characteristic of Thailand, where it is a very rare surname, and India, where it is an extremely rare surname. Likewise, ธารรัตน์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Tarnrat, Tharnrat, ธารรัตน์ | Thailand |
| Thanrat | India, United States, Thailand |