System of a Down is an Armenian-American heavy metal band formed in Glendale, California, in 1994. Since 1997, the band has consisted of founding members Serj Tankian (lead vocals, keyboards); Daron Malakian (guitar, vocals); Shavo Odadjian (bass, backing vocals); along with John Dolmayan (drums), who replaced original drummer Andy Khachaturian in 1997.

The band achieved commercial success with the release of five studio albums, three of which debuted at number one on the US Billboard 200. System of a Down has been nominated for four Grammy Awards, and their song "B.Y.O.B." won a Grammy Award for Best Hard Rock Performance in 2006. The band went on hiatus in 2006 and reunited in 2010. Other than two new songs in 2020 ("Protect the Land" and "Genocidal Humanoidz"), System of a Down has not released any new material since the Mezmerize and Hypnotize albums in 2005. The band has sold over 12 million records worldwide, while two of their singles, "Aerials" and "Hypnotize", reached number one on Billboard's Alternative Songs chart.

All members of System of a Down are of Armenian descent, either born to Armenian immigrants or immigrants themselves.