Sleep is an American stoner/doom metal band from San Jose, California. Guitarist Matt Pike and bassist and vocalist Al Cisneros have been the only constant members throughout the band's history. Critic Eduardo Rivadavia describes them as "perhaps the ultimate stoner rock band" and notes they exerted a strong influence on metal in the 1990s.
The band released their debut album, Volume One, in 1991, after which original fourth member Justin Marler left. Sleep gained wider attention with their second album, Sleep's Holy Mountain, in 1992. However, conflict with the band's record company contributed to their breakup by the end of the decade. Their third album, Dopesmoker, was released after the band's dissolution; both Holy Mountain and Dopesmoker have been acclaimed as doom metal and stoner metal classics. The band reformed in 2009 and have played sporadic live dates internationally since, with Neurosis drummer Jason Roeder replacing original member Chris Hakius. In 2018, Sleep surprise-released their comeback album, The Sciences, on Third Man Records, to further critical acclaim.