Gwar, often stylized as GWAR, is an American heavy metal band formed in Richmond, Virginia, in 1984, composed of and operated by a frequently rotating line-up of musicians, artists, and filmmakers collectively known as Slave Pit Inc. Since the death of frontman Dave Brockie in 2014, the collective has continued recording and performing without any of its founding artists or musicians.

Identified by their distinctively grotesque costumes, Gwar's core thematic and visual concept revolves around an elaborate science fiction-themed mythology which portrays the band members as barbaric interplanetary warriors, a narrative which serves as the basis for all of the band's albums, live shows and media. With over-the-top violent, sexual, and scatological humor typically incorporating social and political satire, Gwar has attracted both acclaim and controversy for its music and stage shows, the latter of which notoriously showcase enactments of graphic violence that result in the audience being sprayed with fake blood, urine, and semen. Such stagecraft regularly leads Gwar to be labeled a "shock rock" band by the media.

Since its formation, Gwar has released 15 studio albums, two live albums, and numerous singles among other recordings, and has sold over 820,000 records in the United States. Fueled largely by the controversies surrounding their concerts, Gwar experienced brief mainstream notoriety during the first half of the 1990s, receiving regular airplay on MTV as well as frequent in-character guest appearances on daytime talk shows, satirizing the topics of censorship and media violence. Though the band's mainstream popularity declined by the end of the 1990s, Gwar has retained a dedicated cult following. The band's extensive videography consists of both live recordings and long-form feature films, most notably 1992's Phallus in Wonderland, which earned a Grammy Award nomination for Best Long Form Music Video. Gwar has also expanded its brand into other areas such as books, comic books board games, beer, whisky barbecue sauce, CBD, e-liquids, toy collectibles, and sex toys.