Mean Streets is a 1973 American neo-noir crime drama film directed by Martin Scorsese, from a screenplay co-written with Mardik Martin. It stars Harvey Keitel and Robert De Niro, along with David Proval, Amy Robinson, Richard Romanus, and Cesare Danova. Scorsese's third feature film, it centers on a group of troubled young men in New York's Little Italy, and centers on many themes the director would later revisit, including the Mafia, Italian-American identity, urban life, and Catholic guilt.

Produced independently and released by Warner Bros. on October 2, 1973, Mean Streets received positive reviews from critics and marked Scorsese's arrival as a major figure of the New Hollywood movement. Robert De Niro won the National Society of Film Critics and the New York Film Critics Circle awards for Best Supporting Actor for his role as "Johnny Boy" Civello.

In 1997, Mean Streets was selected for preservation in the United States National Film Registry by the Library of Congress for being "culturally, historically, or aesthetically significant".

Charlie Cappa, a young Italian American in the Little Italy neighborhood of New York City, is hampered by his feeling of responsibility toward his reckless younger friend John "Johnny Boy" Civello, a small-time gambler and degenerate who refuses to work and owes money to many loan sharks. Charlie is also having a secret affair with Johnny's cousin Teresa, who has epilepsy and is ostracized because of her condition—especially by Charlie's Uncle Giovanni, a powerful mafioso, and is told to stay away from her. Giovanni also wants Charlie to distance himself from Johnny, saying that "honorable men go with honorable men".

Charlie is torn between his devout Catholicism and his illicit Mafia work for Giovanni. Johnny becomes increasingly self-destructive and disrespectful of his Mafia-connected creditors. Failing to receive redemption in the Church, Charlie seeks it through sacrificing himself on Johnny's behalf. At Tony's bar, a loan shark and friend named Michael comes looking for Johnny again to pay his debts; he has been doing so for a few days and is becoming increasingly frustrated, thinking that Johnny is taking advantage of him and that he is not going to pay up, with Charlie promising to convince Johnny.

To his surprise, Johnny insults him and tells him that he is not going to pay back the money. Michael lunges at Johnny, who pulls a gun. After a tense standoff, Michael walks away and Charlie convinces Johnny that they should leave town for a brief period. Teresa insists on coming with them. Charlie borrows a car and they drive off, leaving the neighborhood without incident.

A car that has been following them suddenly pulls up with Michael at the wheel and his henchman, Jimmy Shorts, in the backseat. Jimmy fires several shots at Charlie's car, hitting Johnny in the neck and Charlie in the arm, causing Charlie to crash the car into a fire hydrant. Teresa is injured in the crash. Johnny is seen in an alley staggering toward a white light that is revealed to be a police car, and Charlie gets out of the crashed vehicle and kneels in the water spurting from the hydrant, dazed and bleeding. Paramedics take Teresa and Charlie away while Johnny's fate remains unknown.

Apart from his first actual feature, Who's That Knocking at My Door, this was Scorsese's first feature film of his own design. Director John Cassavetes told him after he completed his second film, Boxcar Bertha, a directing project given to him by early independent filmmaker Roger Corman: "You’ve just spent a year of your life making a piece of shit." This inspired Scorsese to make a film about his own experiences, inspired his upbringing in New York's Little Italy. Cassavetes told Scorsese he should do something like Who's That Knocking at My Door, which Cassavetes had liked.