Anthrax is an American thrash metal band from New York City, formed in 1981 by rhythm guitarist Scott Ian and bassist Dan Lilker. The group is considered one of the leaders of the thrash metal scene from the 1980s and is part of the "Big Four" of the genre, along with Metallica, Megadeth and Slayer. They were also one of the first thrash metal bands (along with Overkill and Nuclear Assault) to emerge from the East Coast. The band's current lineup consists of Scott Ian, drummer Charlie Benante, bassist Frank Bello, vocalist Joey Belladonna and lead guitarist Jonathan Donais. Anthrax's lineup has changed numerous times over their career, leaving Ian as the only constant member of the band. Ian and Benante (who replaced one-time drummer Greg D'Angelo in 1983) are the only two members to appear on all of Anthrax's albums, while Bello has been a member of Anthrax since 1984, replacing Lilker.

After cycling through a number of members, Anthrax released their debut album, Fistful of Metal (1984), with singer Neil Turbin. Turbin was replaced by Joey Belladonna later that year, stabilizing the band's lineup. Anthrax's third album Among the Living (1987), which brought the band mainstream success for the first time, is recognized as one of the greatest thrash metal albums. The band's next two outings, State of Euphoria (1988) and Persistence of Time (1990), further cemented their reputation as one of the most successful thrash metal bands, with the latter giving Anthrax their first Grammy Award nomination. In 1992, Anthrax signed to Elektra Records for $10 million and Belladonna was replaced by John Bush of Armored Saint. Bush's first album with Anthrax, Sound of White Noise (1993), reached number seven on the Billboard 200 chart (their greatest chart success) and spawned the radio hit "Only". Anthrax's subsequent albums with Bush would experience less critical and commercial success; the band would part ways with Elektra following the release of Stomp 442 (1995) due to a lack of promotional support, and Volume 8: The Threat is Real (1998) suffered from the bankruptcy of their record label.

Bush left Anthrax in 2005, after which the band reunited with Belladonna and lead guitarist Dan Spitz. After Belladonna and Spitz's departure in 2007, Anthrax recruited singer Dan Nelson and commenced work on a new album, although Nelson would part ways with the band in 2009. Following a short-lived reunion with Bush, Belladonna rejoined the band for a third time in 2010. Anthrax's first album with Belladonna in 21 years, Worship Music (2011) was released to critical and commercial success, reaching number twelve on the Billboard 200. The band's most recent album to date, For All Kings, was released in 2016.

Anthrax has released 11 studio albums, several other albums, and 26 singles, including collaborating on a single with American hip hop group Public Enemy. Four of the band's studio albums (Among the Living, State of Euphoria, Persistence of Time and Sound of White Noise) have also achieved gold certifications by the RIAA. According to Nielsen SoundScan, Anthrax sold 2.5 million records in the United States from 1991 to 2004, with total worldwide sales of ten million.