Wych Kaosayananda is a Thai film director.
He is the son of famous Thai diplomat "Kaosayananda". He lived and studied in Pakistan, where his father was posted in Islamabad as an ambassador.
His directorial debut was Fah, released in 1998, which at the time was the highest-budgeted film in the history of the Thai film industry but failed in the Thai box office.
His second film and American debut (which he directed under the shortened callname "Kaos") was the 2002 thriller Ballistic: Ecks vs. Sever, which upon release was widely panned by both critics and moviegoers as one of the worst films ever made with the worst title ever made. In March 2007, Rotten Tomatoes ranked the film #1 among "The Worst of the Worst" movie list.