Green Day is an American rock trio formed in 1987. The band has consisted of Billie Joe Armstrong (vocals, guitar), Mike Dirnt (bass guitar, vocals), and Tré Cool (drums, percussion) for the majority of its existence.

Green Day was originally part of the punk rock scene at 924 Gilman Street in Berkeley, California. Its early releases for independent record label Lookout! Records earned them a grassroots fanbase, some of whom felt alienated when the band signed to a major label.

The band has sold over 65 million records worldwide, They also have three Grammy Awards, Best Alternative Album for Dookie, Best Rock Album for American Idiot, and Record of the Year for "Boulevard of Broken Dreams".