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