Cognomen สิทธิทรัพย์ (สิทธิทรัพย์ 
) , in the entire world, is a very rare family name. The family name สิทธิทรัพย์ is habitual in South-eastern Asia, particularly Thailand, where it is a very rare surname. Much less frequently, สิทธิทรัพย์ is the forename as well as the last name.