Toxicity is the second studio album by the American heavy metal band System of a Down, released on September 4, 2001, by American Recordings and Columbia Records. Expanding on their 1998 eponymous debut album, Toxicity incorporates more melody, harmonies, and singing than the band's first album. Categorized primarily as alternative metal and nu metal, the album features elements of multiple genres, including folk, progressive rock, jazz, and Armenian and Greek music, including prominent use of instruments like the sitar, banjo, keyboards, and piano. It contains a wide array of political and non-political themes, such as mass incarceration, the CIA, the environment, police brutality, drug addiction, scientific reductionism, and groupies.
Toxicity was recorded at Cello Studios in Hollywood, California. Over 30 songs were recorded, but the band narrowed the number of songs on the album to 14. The album peaked at number one on both the Billboard 200 and the Canadian Albums Chart, selling 220,000 copies in its first week of release. It was certified sextuple platinum by the Recording Industry Association of America (RIAA) in July 2022, signifying at least six million copies sold in the United States.
In 2021, the staff of Revolver included the album in their list of the "20 Essential Nu-Metal Albums". In 2025, Rae Lemeshow-Barooshian of Loudwire included the album in her list of "the top 50 nu-metal albums of all time", ranking it at second.