Brian Baker (born February 25, 1965) is an American punk rock musician. He is best known as one of the founding members of the hardcore punk band Minor Threat, and as a guitarist in Bad Religion since 1994 alongside Greg Hetson and Brett Gurewitz. In Minor Threat, he originally played bass guitar before switching to guitar in 1982 when Steve Hansgen joined the band, and then moved back to bass after Hansgen's departure. He also founded Dag Nasty in 1985, was part of the original line-up of Samhain, and has had stints in Doggy Style, The Meatmen (with fellow Minor Threat member Lyle Preslar), Government Issue, and Junkyard (a hard rock band).
In 1994 Baker was offered a spot with R.E.M. but declined, opting instead to accept a position in Bad Religion as Brett Gurewitz's replacement. He has also experimented with a more pop direction influenced by U2, with a band called 400. Baker briefly toured with Me First and the Gimme Gimmes in 2005 and appeared on Canadian punk band Penelope's second album (Face au silence du monde).
- Azerrad, Michael (2001). Our Band Could Be Your Life: Scenes from the American Indie Underground, 1981–1991. Little, Brown and Company. ISBN 0-316-78753-1.
- Blush, Steven (2001). Petros, George, ed. American Hardcore: A Tribal History. Feral House. ISBN 978-0-922915-71-2.
- Cogan, Brian (2008). The Encyclopedia of Punk. Sterling. ISBN 978-1-4027-5960-4.