Cognomen ฤทธิศาสตร์ (ฤทธิศาสตร์ 
, Rittisart , Ritthisat ) , globally, is a rare surname. The family name ฤทธิศาสตร์ is habitual in South-eastern Asia, particularly Thailand, where it is a rare surname. Much less frequently, ฤทธิศาสตร์ is the forename as well as the last name.