Blood In Blood Out (also known as Bound by Honor and Blood In Blood Out: Bound By Honor) is a 1993 American epic crime drama film directed by Taylor Hackford, from a screenplay co-written by Jimmy Santiago Baca and Floyd Mutrux. The film follows the intertwining lives of three Chicano relatives from 1972 to 1984. They start out as members of a street gang in East Los Angeles, and as dramatic incidents occur, their lives and friendships are forever changed.

The film stars Jesse Borrego, Benjamin Bratt, Enrique Castillo, and Damian Chapa. The screenplay is partly autobiographical, drawn from Baca’s experiences in street gangs and imprisonment. The film's title refers to the initiation ritual of having to kill someone to enter a gang and, on the reverse end, not being able to leave the gang unless killed.

The film was released by Buena Vista Pictures Distribution on April 30, 1993. Critical reviews were mixed to positive, and Blood In Blood Out was a box office disappointment, but later became a cult classic film among parts of the Mexican-American community.

In 1972, after a violent confrontation with his abusive father, Miklo Velka, a teenager of half-Mexican descent, leaves Las Vegas for East Los Angeles. He moves in with his cousins, Paco and Cruz, who are members of the Vatos Locos gang. Miklo joins the gang following an attack on their rivals, the Tres Puntos. Tres Puntos retaliates by attacking Cruz, permanently damaging his back. When Vatos Locos counterattack the next day, Miklo kills Spider, the leader of Tres Puntos. Fleeing the scene, Paco crashes their car; both he and Miklo are arrested.

The cousins' paths diverge: Miklo is imprisoned in San Quentin for murder, Paco volunteers for military service in the Marine Corps in lieu of prison, and Cruz continues his passion for art. Due to his back pain, Cruz becomes addicted to heroin, leading to the accidental overdose of his 12-year-old brother, Juanito. After the Marines, Paco joins the Los Angeles Police Department, eventually working as an undercover detective for them.

Meanwhile, Miklo finds that San Quentin is run by three racially defined prison gangs: the Black Guerrilla Army (BGA) led by Bonafide, the Aryan Vanguard led by Red Ryder, and La Onda led by Montana Segura. Popeye, a high-ranking member of La Onda, tries to rape Miklo at knifepoint but is stopped by Montana, who finds Popeye's intentions dishonorable. Miklo learns that the only way into La Onda is by killing an inmate from a rival gang. He forms a rapport with Aryan Vanguard associate Big Al, then kills him in the prison kitchen. Now initiated, Miklo rises through the La Onda ranks, eventually joining its Ruling Council.

After serving nine years, Miklo is granted parole. On the outside, disgusted by his menial job, he joins in an armed robbery. The heist goes poorly and Miklo is intercepted by Paco, who tries to persuade him to surrender his weapon and resolve the situation peacefully. Miklo instead starts to flee, and Paco shoots him in the leg. The leg is amputated, and Miklo is sent back to prison.

Miklo notices that cocaine use is now rampant, driven by competing supplies from the BGA and La Onda council member Carlos. The Aryan Vanguard want to partner with Carlos as his supplier, offering to help Carlos take the BGA out of the cocaine business. Montana, against La Onda being in the drug trade, warns that the Aryans want to start a war between the Black and Chicano inmates. The Council votes in agreement with Montana, resulting in Carlos and some others leaving La Onda to work with the Aryan Vanguard.