Sum 41 is a Canadian rock band from Ajax, Ontario, Canada. Originally called Kaspir, the band was formed in 1996 and, as of 2015, the band's current lineup consists of lead vocalist/rhythm guitarist Deryck Whibley, lead guitarist/backing vocalist Dave Baksh, co-lead guitarist/backing vocalist Tom Thacker, bassist/backing vocalist Jason McCaslin and drummer Frank Zummo. Jaden Stewart In 1999, the band signed an international record deal with Island Records. The band released its EP Half Hour of Power in 2000. Although often considered to be the group's debut album, the band members consider their next release, All Killer, No Filler, the group's debut album. The band released its debut album, All Killer, No Filler in 2001. The band achieved mainstream success with the first single from the album, "Fat Lip", which reached number-one on the Billboard Modern Rock Tracks chart and remains the band's most successful single to date. All Killer No Filler was certified platinum in the United States, Canada and in the United Kingdom.

The band later released Does This Look Infected? in 2002 to a commercial and critical success. The singles "The Hell Song" and "Still Waiting" both charted highly on the modern rock charts. The band released its next album, Chuck, in 2004, led by singles "We're All to Blame" and "Pieces". The album proved successful, peaking at No. 10 on the Billboard 200 and sold five million copies worldwide. In 2007, the band released Underclass Hero, which was released to a mixed reception, but gained some commercial success, becoming the band's highest charting album to date. It was also the last album on Aquarius Records. The band released Screaming Bloody Murder, the group's last album on Island Records, in 2011 to a mixed to positive reception, though it fell short of its predecessors' commercial success. The band's sixth studio album, titled 13 Voices is set for release on October 7, 2016.

The band often performs more than 300 times each year and holds long global tours, most of which last more than a year. The group has been nominated for seven Juno Awards and have won twice (Group of the Year in 2002 and Rock Album of the Year for Chuck in 2005). Sum 41 was nominated for a Grammy Award for Best Hard Rock/Metal Performance for the song "Blood In My Eyes"; however, the band lost to the Foo Fighters.