Adrian Monk is the fictional protagonist of the USA Network television series Monk, played by Tony Shalhoub. Monk is a legendary former homicide detective for the San Francisco Police Department. He suffers from acute obsessive-compulsive disorder, which, severely intensified by the murder of his wife, resulted in his suspension from the department. Since then, he has been working as a private consultant for the department, hoping to be reinstated.

According to series co-creator David Hoberman, Monk is partly based on himself, and also on other fictional detectives, such as Lt. Columbo 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."

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.