Two teenage gangs struggle for control on the Upper West Side in New York City in the 1950s. The Jets, a white gang led by Riff, brawl with the Sharks, a group of Puerto Ricans led by Bernardo. Lieutenant Schrank and Officer Krupke arrive and break it up. The Jets decide to challenge the Sharks to a rumble after an upcoming dance.
Riff wants his best friend Tony, co-founder of the Jets who left the gang, to fight at the rumble. Riff invites Tony to the dance, but Tony tells Riff that he senses something important is coming, which Riff suggests could happen at the dance. After more persuasion, Tony agrees to go. Bernardo's younger sister, Maria, tells her best friend and Bernardo's girlfriend, Anita, how excited she is about the dance. At the dance, the gangs and their girls refuse to intermingle. Tony arrives; he and Maria fall in love, but Bernardo angrily demands that Tony stay away from her. Riff proposes a meeting with Bernardo at Doc's drug store at midnight to settle the rules for the rumble.
Maria is sent home; Anita argues that Bernardo is overprotective of Maria, and they compare the advantages of Puerto Rico and the United States. Tony sneaks onto Maria's fire escape, where they reaffirm their love. Krupke, who suspects the Jets are planning something, visits them and warns them not to cause trouble. The Sharks arrive, and the gangs agree to have the showdown the following evening under the highway, with a one-on-one fistfight. When Schrank arrives, the gangs feign friendship. Schrank orders the Sharks out and unsuccessfully tries to discover information about the fight.
The next day at the bridal shop where they work, Anita accidentally tells Maria about the rumble. Tony arrives to see Maria. Anita, shocked, warns them about the consequences if Bernardo learns of their relationship. Maria makes Tony promise to prevent the rumble. Tony and Maria fantasize about their wedding.
The gangs approach the area under the highway. Tony arrives to stop the fight, but Bernardo antagonizes him. Unwilling to watch Tony be humiliated, Riff initiates a knife fight. Tony tries to intervene, which leads to Bernardo stabbing and killing Riff. Tony then kills Bernardo with Riff's knife, and a melee ensues. Police sirens blare, and everyone flees, leaving behind the dead bodies. Maria waits for Tony on the rooftop of her apartment building; her fiancé Chino arrives and tells her what happened. When Tony arrives, he asks for her forgiveness before he turns himself in to the police. Maria confirms her love for him and asks Tony to stay with her.
The Jets and their new leader, Ice, reassemble outside a garage and focus on reacting to the police. Anybodys arrives and warns them that Chino is now after Tony with a gun. Ice sends the Jets to warn Tony. A grieving Anita enters the apartment while Tony and Maria are in the bedroom. The lovers arrange to meet at Doc's, where they will pick up getaway money to elope. Anita spots Tony leaving through the window and chides Maria for the relationship with Bernardo's killer, but Maria convinces her to help them elope. Schrank arrives and questions Maria about the rumble. Maria sends Anita to tell Tony that Maria is detained from meeting him.
When Anita reaches Doc's, the Jets harass her until Doc intervenes. Anita angrily says that Chino has killed Maria. Doc banishes the Jets, gives Tony his getaway money in the basement and delivers Anita's message. Tony, distraught, runs into the streets, shouting for Chino to kill him too. In the playground next to Doc's, Tony spots Maria and they run toward each other, only for Chino to shoot Tony. The gangs arrive to find Maria holding Tony, who dies in her arms. Maria stops the gangs from fighting, takes the gun from Chino and threatens to shoot everyone, blaming their hate for the deaths. Schrank, Krupke and Doc arrive, and the gangs form a funeral procession, with Maria following. The police arrest Chino and lead him away.
Natalie Wood as Maria, Bernardo's younger sister and Chino's arranged fiancée,[4] who falls in love with Tony
Marni Nixon as Maria's singing voice (also Anita's singing voice in Quintet)
Richard Beymer as Tony, co-founder and one-time member of the Jets and best friend of Riff, who works at Doc's drugstore and falls in love with Maria
Jimmy Bryant as Tony's singing voice
Russ Tamblyn as Riff, leader of the Jets, best friend of Tony
Tucker Smith as Riff's singing voice for "Jet Song"
Rita Moreno as Anita, Bernardo's girlfriend, and Maria's closest confidante
Betty Wand as Anita's singing voice for "A Boy Like That"
George Chakiris as Bernardo, leader of the Sharks, older brother of Maria and Anita's boyfriend
Simon Oakland as Police Lieutenant Schrank, a hard-boiled plainclothes detective
Ned Glass as Doc, drugstore owner, Tony's boss; a decent, elderly man
William Bramley as Police Sergeant Krupke, a brusque beat cop (Bramley played the role in the original Broadway production.)
John Astin as Glad Hand, well-meaning but ineffective social worker
Penny Santon as Madam Lucia, bridal shop owner
Tucker Smith as Ice (a character created for the film), Riff's lieutenant; becomes leader of the Jets after Riff's death
Tony Mordente as Action, a short-tempered Jet.
David Winters as A-Rab, Baby John's best friend
Eliot Feld as Baby John, the youngest member of the Jets; a relative innocent
Bert Michaels as Snowboy
David Bean as Tiger
Robert Banas as Joyboy
Anthony 'Scooter' Teague as Big Deal
Harvey Evans (Harvey Hohnecker) as Mouthpiece
Tommy Abbott as Gee-Tar
Susan Oakes as Anybodys, a tomboy and wannabe Jet
Gina Trikonis as Graziella, Riff's girlfriend
Carole D'Andrea as Velma, Ice's girlfriend
Rita Hyde d'Amico as Clarice, Big Deal's girlfriend
Pat Tribble as Minnie, Baby John's girlfriend
Francesca Bellini as Debby, Snowboy's girlfriend
Elaine Joyce as Hotsie, Tiger's girlfriend
Jose De Vega as Chino Martin, Bernardo's best friend, who is the arranged fiancé of Maria[4]
Jay Norman as Pepe, Bernardo's lieutenant
Gus Trikonis as Indio, Pepe's best friend
Eddie Verso as Juano
Jaime Rogers as Loco
Larry Roquemore as Rocco
Robert Thompson as Luis
Nick Covacevich as Toro
Rudy Del Campo as Del Campo
Andre Tayir as Chile
Yvonne Wilder as Consuelo, Pepe's girlfriend (In credits as Yvonne Othon)
Suzie Kaye as Rosalia, Indio's girlfriend
Joanne Miya as Francisca, Toro's girlfriend
Maria Jimenez Henley as Teresita, Juano's girlfriend
Luci Stone as Estella, Loco's girlfriend
Olivia Perez as Margarita, Rocco's girlfriend