Mystic River is a 2003 American drama film directed, co-produced and scored by Clint Eastwood, starring Sean Penn, Tim Robbins, Kevin Bacon, Laurence Fishburne, Marcia Gay Harden, Laura Linney and Emmy Rossum.

Directed by Clint Eastwood, the mysterious drama Mystic River is based on the novel by Dennis Lehane and adapted by screenwriter Brian Helgeland. Set in an Irish neighborhood in Boston. When they were kids growing up together in a rough section of Boston, Jimmy Markum (Penn), Dave Boyle (Robbins) and Sean Devine (Bacon) spent their days playing stickball on the street, the way most boys did in their blue-collar neighborhood of East Buckingham. Nothing much ever happened, that is, until Dave was forced to take a ride that would change all of their lives forever.

Twenty-five years later, the three find themselves thrust back together by another life-altering event—the murder of Jimmy's 19-year-old daughter. Now a homicide detective, Sean and his partner (Fishburne) are assigned to the case. They must also stay one step ahead of Jimmy, a man driven by an all consuming rage to find his daughter's killer. Connected to the crime by a series of circumstances, Dave is forced to confront the demons of his own past. Demons that threaten to destroy his marriage and any hope he may have for a future. As the investigation tightens around these three friends, an ominous story unfolds that revolves around friendship, family and innocence lost too soon.

Mystic River was well received by critics as well as viewers. The film has an 87% approval rating based on 191 reviews from critics at the review aggregator website Rotten Tomatoes, and an even higher rating of 95% from its "Top Critics". At the website MetaCritic, which utilizes a normalized rating system, the film earned a rating of 84/100 ("universal acclaim") based on 42 reviews. Peter Travers of Rolling Stone wrote"Clint Eastwood pours everything he knows about directing into Mystic River. His film sneaks up, messes with your head, and then floors you. You can't shake it. It's that haunting, that hypnotic." The Sun wrote that the film was "a haunting masterpiece and probably (Eastwood's) best film to date".

The film earned $156,822,020 worldwide with$90,135,191 in the U.S. and $66,686,829 in the international box office, which is significantly higher than the film's $30,000,000 budget.

The film was nominated for Academy Awards for Best Picture, Best Director, Best Actor, Best Adapted Screenplay, Best Supporting Actress and Best Supporting Actor. Sean Penn won Best Actor and Tim Robbins won Best Supporting Actor, making Mystic River the first film to win both awards since Ben-Hur in 1959.