Cognomen Ritthisak (Ritthisak 
) , in the entire world, is a rare last name. The last name Ritthisak is habitual in Thailand, where it is a rare surname, and Switzerland, where it is a very rare surname. Also, Ritthisak is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Ritthisak | Cambodia, Switzerland, Thailand |