Family name ฤทธิมาศ (ฤทธิมาศ 
, Rithimat, Ritthimat ) , around the world, is a rare last name. The family name ฤทธิมาศ is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname.
| VARIANT | COUNTRY |
|---|---|
| Ritthimat, Ritthamart, ฤทธิมาศ | Thailand |
Ritthamas, and Tharuetimat