Surname วิฤทธิ์ (Wirit 
, วิฤทธิ์ ) , in all the world, is a rare cognomen. The last name วิฤทธิ์ is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname, and Indonesia, where it is a very rare surname. Likewise, วิฤทธิ์ is the forename as well as the last name.