Surname สิทธิ์ชัย (สิทธิ์ชัย 
, Sitchai ) , across the world, is a very rare cognomen. The cognomen สิทธิ์ชัย is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname. Much more frequently, สิทธิ์ชัย is the forename as well as the last name.