The film opens in 1984, focusing on three young black male youths, Tre, Doughboy, and Ricky, as they grow up in South Central, Los Angeles. Tre Styles is an intelligent young student, but encounters disciplinary problems at a young age. His mother Reva Devereaux (Angela Bassett), decides it would be best for her son if Tre were to live with his father, Furious Styles (Laurence Fishburne). Furious is a no nonsense disciplinarian who teaches his son how to be a man. Tre begins his new life in South Central L.A. and reunites with old friends Doughboy, Ricky, and Little Chris though shortly after being reunited, Doughboy and Chris are arrested for shoplifting from a local convenience store.
Seven years later in 1991, the three boys lead very different lives. Tre (Cuba Gooding, Jr.) is a high school senior aspiring to become a college man, Ricky (Morris Chestnut) an All-American football player, and Doughboy (Ice Cube) a crack dealing gangster. The film offers a keen insight on racial inequality, drugs, sex, and gang violence.
Doughboy has just been released from prison and spends most of the time hanging out with friends Chris (now confined to a wheelchair), Monster and Dookie. Ricky is a star running back at Crenshaw High School. He has a son with his girlfriend Shanice (Alysia Rogers) and is being recruited by the University of Southern California, but needs to earn a minimum SAT score of 700 to receive an athletic scholarship. Tre also attends Crenshaw High School with Ricky and also has a girlfriend, Brandi (Nia Long). Tension exists between the two because he wants to have a sexual relationship with Brandi, who resists the idea because of her Catholic faith.
Tre is torn by his desire to be a success and live up to his father's expectation and the pull of peer pressure to be more involved in the local gang culture of Doughboy and his crew. The climax of the film depicts Ricky's murder by members of a the local Crips, with whose leader he had a minor conflict, ironically after the audience learns that he has achieved the 700 SAT score necessary to attend USC. Doughboy, Monster, and Dookie intend to avenge Ricky's death. Tre, who is Rickys best friend, takes Furious' gun, but is stopped by him before leaving the house. Furious convinces Tre not to take the gun and seek revenge and Tre seems to relent, but he soon joins Doughboy and his friends on a revenge mission. Half way through the trip, Tre realizes his father was correct, asks Doughboy to pull the car over, and returns home. Doughboy and his two friends proceed and avenge Ricky's murder, gunning down his killers in cold blood.
The film ends the following morning with a conversation between Tre and Dough Boy. Dough Boy understands why Tre left the revenge mission and both laments the circumstances that exist in South Central and questions whether or not they are locked in an unending cycle of violence. The end titles reveal that Doughboy was murdered two weeks later, and Tre went on to college with Brandi in Atlanta (with Tre enrolling at Morehouse, and Brandi at nearby Spelman).