System of a Down, also known by the acronym SOAD and often shortened to System, is an American four-piece rock band from Southern California, formed in 1994. The band currently consists of four Armenian-Americans: Daron Malakian (vocals, guitar), Serj Tankian (lead vocals, occasional keyboards and rhythm guitar), Shavo Odadjian (bass, background vocals) and John Dolmayan (drums).

The band achieved commercial success with the release of five studio albums, of which three debuted at number one on the Billboard 200. System of a Down has been nominated for four Grammy Awards, and their song "B.Y.O.B." won the Best Hard Rock Performance of 2006. The group went on hiatus in August 2006 and reunited in November 2010, embarking on a tour for the following three years. System of a Down have sold over 40 million records worldwide.