Worldwide, เธียรศิริ (เธียรศิริ 
) is a very rare mostly masculine, but uncommonly feminine first name. The given name เธียรศิริ is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare mostly masculine, but infrequently female name. Very seldom, เธียรศิริ is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| เธียรศิริ | Thailand |