Adrian Monk, portrayed by Tony Shalhoub, is the title character and protagonist of the USA Network television series Monk. He is a renowned former homicide detective for the San Francisco Police Department. Monk has obsessive–compulsive disorder (OCD) and multiple phobias, all of which intensified after the murder of his wife Trudy, resulting in his suspension from the department. He works as a private police homicide consultant and undergoes therapy with the ultimate goal of overcoming his grief, taking control of his phobias and disorder, and being reinstated as a police detective.

Series co-creator David Hoberman says that he based Monk partly on himself, and also on other fictional detectives, such as Lt. Columbo, Hercule Poirot and Sherlock Holmes. Other actors considered for the role included Dave Foley, John Ritter, Henry Winkler, Stanley Tucci, Alfred Molina and Michael Richards. The network eventually chose Shalhoub because they felt he could "bring the humor and passion of Monk to life". Stanley Tucci and Alfred Molina had guest appearances on Monk, with Tucci appearing in season 5 episode "Mr. Monk and the Actor", and Molina appearing in season 6 episode "Mr. Monk and the Naked Man".

Both Monk and Shalhoub have garnered many accolades. Monk was included in Bravo's list of The 100 Greatest Television Characters of All Time, and Shalhoub has won various awards for his portrayal, including a Golden Globe Award, three Primetime Emmy Awards and two Screen Actors Guild Awards.