Sly and the Family Stone was an American band formed in San Francisco, California, in 1966 and active until 1983. Their work, which blended elements of funk, soul, psychedelic rock, gospel, and R&B, became a pivotal influence on subsequent American popular music. Their core line-up was led by singer-songwriter, producer, and multi-instrumentalist Sly Stone, and included Stone's siblings Freddie Stone (guitar, vocals) and Rose Stone (keyboard, vocals) alongside Cynthia Robinson (trumpet, vocals), Greg Errico (drums), Jerry Martini (saxophone), and Larry Graham (bass, vocals). The band was the first major American rock group to have a racially integrated, mixed-gender lineup.

Formed in 1966, the group synthesized a variety of musical genres to pioneer the emerging "psychedelic soul" sound. They released a series of Top 10 Billboard Hot 100 hits such as "Dance to the Music" (1968), "Everyday People" (1968), “Hot Fun in the Summertime” (1969), and "Thank You (Falettinme Be Mice Elf Agin)" (1969), as well as critically acclaimed albums such as Stand! (1969), which combined pop sensibility with social commentary. In the 1970s, it transitioned into a darker and less commercial funk sound on releases such as There's a Riot Goin' On (1971) and Fresh (1973), proving as influential as their early work. By 1975, drug problems and interpersonal clashes led to dissolution, though Sly continued to record and tour with a new rotating lineup under the name "Sly and the Family Stone" until drug problems forced his effective retirement in 1987.

The work of Sly and the Family Stone influenced the sound of subsequent American funk, pop, soul, R&B, and hip hop music. Music critic Joel Selvin wrote, "there are two types of black music: black music before Sly Stone, and black music after Sly Stone". In 2010, they were ranked 43rd in Rolling Stone's 100 Greatest Artists of All Time, and three of their albums are included on the most recent version of Rolling Stone's 500 Greatest Albums of All Time. The band was inducted into the Rock and Roll Hall of Fame in 1993.

Sylvester Stewart was born into the Dallas, Texas, family of K.C. and Alpha Stewart, followers of the Church of God in Christ (COGIC), who encouraged musical expression in the household. After the Stewarts moved to Vallejo, California, the youngest four children (Sylvester, Freddie, Rose, and Vaetta) formed "The Stewart Four", who released a local 78 RPM single, "On the Battlefield of the Lord" b/w "Walking in Jesus' Name".

While attending high school, Sylvester and Freddie joined student bands. One of Sylvester's high school musical groups was a doo-wop act called the Viscaynes. The Viscaynes released a few local singles, and Sylvester recorded several solo singles under the name "Danny Stewart".

By 1964, Sylvester had become Sly Stone. He became a disc jockey for San Mateo, California-located R&B radio station KSOL, where he included white performers such as the Beatles and the Rolling Stones in his playlists. During the same period, he worked as a record producer for Autumn Records, producing for San Francisco-area bands such as the Beau Brummels and the Mojo Men. One of the Sylvester Stewart-produced Autumn singles, Bobby Freeman's "C'mon and Swim", was a national hit. Stewart recorded unsuccessful solo singles while at Autumn.

In 1966, Sly Stone formed a band called Sly & the Stoners, which included acquaintance Cynthia Robinson on trumpet. Around the same time, Freddie founded a band called Freddie & the Stone Souls, which included Greg Errico on drums, and Ronnie Crawford on saxophone. At the suggestion of Stone's friend, saxophonist Jerry Martini, Sly and Freddie combined their bands, creating Sly and the Family Stone in November 1966. At first the group was called Sly Brothers and Sisters but after their first gig at the Winchester Cathedral, a night club in Redwood City, California, they changed the name to Sly & the Family Stone. Since both Sly and Freddie were guitarists, Sly appointed Freddie the official guitarist for the Family Stone, and taught himself to play the electronic organ. Sly also recruited Larry Graham, Robinson's cousin, to play bass guitar.

Vaetta Stewart wanted to join the band as well. She and her friends, Mary McCreary and Elva Mouton, had a gospel group called the Heavenly Tones. Sly recruited the teenagers directly out of high school to become Little Sister, Sly and the Family Stone's background vocalists.