Cognomen ฤทธิ์รงค์ (ฤทธิ์รงค์ 
) , all over the world, is a very rare surname. The family name ฤทธิ์รงค์ is habitual in South-eastern Asia, particularly Thailand, where it is a very rare surname. More frequently, ฤทธิ์รงค์ is the forename as well as the last name.