Fall Out Boy (commonly abbreviated as FOB) is an American band from Wilmette, Illinois, (a suburb of Chicago) that formed in 2001. The band consists of Patrick Stump (lead vocals, rhythm guitar, and primary composer), Pete Wentz (bass guitar, backup vocals, and primary lyricist), Joe Trohman (lead guitar), and Andy Hurley (drums).

Fall Out Boy was formed in early 2001 by friends Joe Trohman and Pete Wentz. The two had played in various bands in the Chicago area. They decided they wanted to start a band that was more similar to bands they listened to growing up such as Green Day, Descendents, and The Smiths. Trohman met high schooler Patrick Stump in a Borders Bookstore. Trohman introduced himself to Stump when he overheard him talking about the band Neurosis, in which they shared a mutual interest. Stump auditioned as a drummer, but as soon as his vocal range was discovered, he became the lead singer. Two other Chicago musicians were recruited to play drums and guitar. The following year, the band debuted with a self-released demo and followed it up with the May 28, 2002 release of Split EP, which featured Project Rocket, on Uprising Records. The group released a mini-LP, Fall Out Boy's Evening Out with Your Girlfriend, on Uprising Records, in 2003.