Family name กุศลศักดิ์ (Charusak 
, กุศลศักดิ์ , Kusolsak ) , around the globe, is a very rare surname. The family name กุศลศักดิ์ is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname. Also, กุศลศักดิ์ is the forename as well as the last name.