Acid King is an American stoner metal band from San Francisco, California. It was formed in 1993 by frontwoman Lori S., drummer Joey Osbourne and bassist Peter Lucas. Acid King have since recorded four studio albums and two EPs with a series of bassists.

The band's name was inspired by the crimes of Ricky Kasso, who murdered his friend Gary Lauwers in Northport, New York on June 19, 1984. Kasso was nicknamed "Acid King" by his peers due to his chronic hallucinogenic drug use. The band's self-titled debut EP features a photograph of Kasso on its cover. The band itself has also been featured in two books – The Encyclopedia of Heavy Metal and the A to Z of Doom, Gothic & Stoner Metal – both published in 2003.