Cognomen Rattanajan (Rattanajan 
) , in the world, is a rare last name. The last name Rattanajan is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname.
Sinn, Chutinart, Chachchaya, Watthana, Tippawan, Pitsinee, Padiphan, Boonlert, Wirawan, Naratip, Janjira, Jannapa, Piyanan, Kitsana, Charida, Amonrat, Suchada, Sudarat, Tattep, Jariya, Kyekoon, Kasorn, Janja, Amara, Annop, Surat, Samai, Yupa, Yada, Jaja, Pongsagon, and Kasamaporn