Beastie Boys were an American hip hop/rap rock group from New York City, formed in 1981. The group was composed of Adam "Ad-Rock" Horovitz (vocals, guitar), Adam "MCA" Yauch (vocals, bass), and Michael "Mike D" Diamond (vocals, drums, programming). Beastie Boys were formed out of members of experimental hardcore punk band The Young Aborigines, which was formed in 1979, with Diamond on drums, Jeremy Shatan on bass guitar, John Berry on guitar, and Kate Schellenbach later joining on percussion. When Shatan left New York City in mid-1981, Yauch replaced him on bass and the resulting band was named Beastie Boys. Berry left shortly thereafter and was replaced by Horovitz.

After achieving local success with the 1983 comedy hip hop single "Cooky Puss", Beastie Boys made a full transition to hip hop, and Schellenbach left. They toured with Madonna in 1985 and a year later released their debut album, Licensed to Ill (1986), the first rap album to top the Billboard 200 chart. Their second album, Paul's Boutique (1989), composed almost entirely of samples, was a commercial failure that later received critical acclaim. Check Your Head (1992) and Ill Communication (1994) found mainstream success, followed by Hello Nasty (1998), To the 5 Boroughs (2004), The Mix-Up (2007), and Hot Sauce Committee Part Two (2011).

Beastie Boys have sold 20 million records in the United States and had seven platinum-selling albums from 1986 to 2004. They are the biggest-selling rap group since Billboard began recording sales in 1991. In 2012, they became the third rap group to be inducted into the Rock and Roll Hall of Fame. In the same year, Yauch died of cancer and Beastie Boys disbanded. The remaining members have released several retrospective works, including a book, a documentary, and a career-spanning compilation album.