Red John is a fictional character and the primary antagonist of the CBS crime drama The Mentalist for the first five seasons and in the first half of the sixth season. As a serial killer, he is believed to have begun his killing spree in 1988, and has, with his operatives and acolytes, killed more than 70 people in California, Nevada, and Mexico. Five years prior to the action of the first episode, he murdered the wife and daughter of Patrick Jane, making Jane his dedicated nemesis.

The Mentalist is an American drama television series that ran from September 23, 2008, until February 18, 2015, broadcasting 151 episodes over seven seasons, on CBS. Created by Bruno Heller, who was also its executive producer, the show follows former "psychic" Patrick Jane, who is a consultant to the California Bureau of Investigation (CBI), and his boss, senior agent Teresa Lisbon, using the highly developed observational skills he previously employed to "read" people's minds.