Jørn Lier Horst (born 27 February 1970, in Bamble, Telemark) is a Norwegian author of crime fiction and a former Senior Investigating Officer at Vestfold Police district. He made his debut in 2004 with the crime novel Key Witness, based on a true murder story. The detective character in his novels is William Wisting. He has also written children books, including a series named Clue.