Insomniac is the fourth studio album by the American rock band Green Day, released on October 10, 1995, by Reprise Records. It was recorded at Hyde Street in San Francisco, and the band prioritized high-energy takes during the recording sessions. Released as the follow-up to the band's multi-platinum breakthrough Dookie, Insomniac featured a heavier, hardcore punk sound, with bleaker lyrics than its predecessor. Lyrically, the album discusses themes such as alienation, anxiety, boredom, and drug use. Insomniac also served as a reaction to many early fans who had turned their backs on the band after it achieved mainstream success with Dookie.

Green Day is an American rock band formed in the East Bay of California in 1987 by lead vocalist and guitarist Billie Joe Armstrong and bassist and backing vocalist Mike Dirnt, with drummer Tré Cool joining in 1990. In 1994, their major-label debut Dookie, released through Reprise Records, became a breakout success and eventually shipped over 10 million copies in the U.S. Alongside fellow California punk bands Bad Religion, the Offspring, Rancid, NOFX, Pennywise and Social Distortion, Green Day is credited with popularizing mainstream interest in punk rock in the U.S.