Cognomen เธียรสิริ (เธียรสิริ 
) , in all the world, is a very rare last name. The cognomen เธียรสิริ is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname. Likewise, เธียรสิริ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| เธียรสิริ | Thailand |