Family name ยศศักดิ์ (ยศศักดิ์ 
, Title 
, Yossak 
) , in the world, is a rare cognomen. The last name ยศศักดิ์ is habitual in Taiwan, where it is a rare surname, Thailand, and Myanmar. In absolute terms, it is commonest in Thailand, the United States, and Taiwan. Likewise, ยศศักดิ์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Yotsak, ยศศักดิ์ | Thailand |
| Title | Taiwan, United States, Thailand, Canada, Myanmar |
| Yossak | United States, Israel, Thailand |