Attack of the Killer B's is a compilation album of B-sides, covers and rarities by the thrash metal band Anthrax and the band's last audio album released before vocalist John Bush replaced longtime Anthrax vocalist Joey Belladonna in 1992. The album was released in June 1991 by Megaforce Worldwide/Island Entertainment. The "B's" in the album's title refers to b-sides previously unreleased and compiled for a single release. In 1992 the album was nominated for a Grammy Award in the category Best Metal Performance.

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 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 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.