Cognomen สกุลสิทธิ์ (สกุลสิทธิ์ 
) , globally, is a very rare family name. The family name สกุลสิทธิ์ is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname. Likewise, สกุลสิทธิ์ is the forename as well as the last name.