Family name พจนฤทธิ์ (พจนฤทธิ์ 
, Pojjanarit , Phanthalit ) , all around the world, is a very rare surname. The family name พจนฤทธิ์ is habitual in South-eastern Asia, particularly Thailand, where it is a very rare surname. Also, พจนฤทธิ์ is the forename as well as the last name.