Black Flag is an American hardcore punk band formed in 1976 in Hermosa Beach, California by Greg Ginn, the band's guitarist, primary songwriter, and sole constant member, and vocalist Keith Morris. During Black Flag's initial 10-year existence, the band went through 16 distinct lineups involving 17 different musicians. Aside from Ginn, the longest-lasting members were bassist Chuck Dukowski, vocalist Henry Rollins, vocalist Morris, and drummer Roberto "Robo" Valverde. The 1983–1985 lineup of Ginn, Rollins, bassist Kira Roessler, and drummer Bill Stevenson recorded four albums and three EPs together in a sixteen-month period. After breaking up in 1986 and briefly reuniting in 2003, Black Flag announced another reunion in January 2013, followed by a third in 2019. In 2013, Morris along with other former member of Black Flag who were estranged from Ginn, formed FLAG and started touring and performing Black Flag songs. Following Black Flag's 2019 reunion tour, Ginn recruited new musicians in 2025 for concerts.