->''I don't want to waste my time,\\
Become another casualty of society,\\
I'll never fall in line,\\
Become another victim of your conformity,\\
And back down.''
-->"Fat Lip"

'''Sum 41''' is a pop punk rock band from Ontario, Canada, formed in 1996 by vocalist/guitarist Deryck Whibley and drummer Steve Jocz "[[PunBasedTitle some 41 days into the summer]]." They were soon joined by lead guitarist Dave Baksh and after a set of bass guitarist they finally settled on Jason "Cone" [=McCaslin=] in 1999. Their first album (''All Killer, No Filler'') was released in 2001 and spawned their most successful single, "Fat Lip".

Their follow-up album ''Does This Look Infected?'' was released in 2002. It featured a darker sound and also more serious lyrical themes. This continued onto their third album ''Chuck'', released in 2004. In 2006, Baksh left the band to focus on his own band Brown Brigade. He was replaced by Tom Thacker, who was initially only a live member, while their 2007 album ''Underclass Hero'' was recorded as a trio. Thacker became an official member in 2009 and helped to co-write title track for (but did not record on) their fifth studio album ''Screaming Bloody Murder'', released in 2011.

The band’s music is primarily pop punk and punk rock, though they have diversified over the years. They moved from pop punk (with some rap rock) on ''All Killer, No Filler'', to melodic hardcore on ''Does This Look Infected?'' and ''Chuck'' (with the latter having alternative metal influences and lighter alternative rock), back to pop punk with ''Underclass Hero'', and back to melodic hardcore with ''Screaming Bloody Murder''.

Drummer Steve Jocz left the band in April of 2013, leaving Deryck as the sole remaining founding member. He was replaced by Frank Zummo, who performed on their sixth album, 13 Voices. The new album also marks the return of lead guitarist Dave Baksh, making Sum 41 a 5 piece as Tom remained with the band as well.

!!!Members (current members in bold)
* '''Deryck Whibley''' - lead vocals, rhythm guitar, keyboards, occasional drums (1996 - present)
* Steve Jocz - drums, backing and occasional lead vocals (1996 - 2013)
* '''Dave "Broundsound" Baksh''' - lead guitar, backing vocals (1998 - 2006) (2015 - present)
* '''Jason "Cone" [=McCaslin=]''' - bass, backing vocals (1999 - present)
* '''Tom "Brown Tom" Thacker''' - guitar, backing vocals, keyboards (2009 - present; 2006 - 2009 as touring member)
* '''Frank Zummo''' - drums, backing vocals (2015 - present)

* "Half Hour of Power" (2000, EP)
* "All Killer, No Filler" (2001)
* "Does This Look Infected?" (2002)
* "Chuck" (2004)
* [[LiveAlbum "Go Chuck Yourself"]] (2005, released in Japan as Happy Live Surprise)
* "Underclass Hero" (2007)
* [[GreatestHitsAlbum "All the Good Shit"]] (2008)
* "Screaming Bloody Murder" (2011)
* "Thirteen Voices" (2016)

!They provide examples of the following tropes:
* AccidentalMisnaming: Tom's nickname, Brown Tom comes from Steve almost calling him Brownsound, the nickname of then-former guitarist Dave Baksh.
* TheAlcoholic: Deryck admitted, that he used to drink very excessively. He eventually stopped after he collapsed and doctors told him, that if he had one more drink, he would probably die.
* AllDrummersAreAnimals: Steve.
* AlterEgoActing: As Pain for Pleasure (see below). Also in music video for Still Waiting, they performed as The Sums and were renamed. Deryck was Sven, Dave was Holmes, Steve was Sergio and Cone was Thurston.
* AscendedExtra: Tom, as of 2009.
* BreakupSong: “Pieces”, “Time for You to Go”, “What Am I to Say”, “Blood in My Eyes” and “Baby, You Don’t Wanna Know”. Note that 4 of these 5 songs were recorded after the divorce from Music/AvrilLavigne
* CallBack: Bridge to the song Subject to Change (found on japanese version of Chuck) is the same as at the end of No Reason (another, earlier song from the same album). And of course, chorus of the former song was later re-used as chorus to Underclass Hero.
* CanadaEh: The band hail from Ajax, a sleepy town in Ontario.
* CarefulWithThatAxe: “Mr. Amsterdam”
* CelebritySong: “A.N.I.C.”
* CerebusSyndrome: ''Half Hour of Power'' and ''All Killer, No Filler'' were both very upbeat, MTV-friendly pop-punk albums. They were followed by the [[NewSoundAlbum hardcore/horror punk inspired]] ''Does This Look Infected?'' and, after that, the very sombre ''Chuck'' and equally so ''Screaming Bloody Murder'', making the much lighter ''Underclass Hero'' a BreatherEpisode. ''Thirteen Voices'' continues the darker sound.
* CountryMatters: A.N.I.C., which stands for Anna Nicole Is (a) Cunt.
** Concerts [[CrossesTheLineTwice take this a step further]] with Deryck introducing the song as "Anna Nicole Is A Fucking Stupid Cunt!"
** Also in "Ma Poubelle". The song contains a line "Tu sais tu es ma petite fleur, avec une plotte qui est comme du beurre", which translates to "You know you are my little flower, with a cunt that's like butter".
* DarkerAndEdgier: Does This Look Infected? was this to All Killer, No Filler and Chuck was this to Does This Look Infected and finally Screaming Bloody Murder is this to Underclass Hero.
* DisproportionateRetribution: In Basketball Butcher, Stevo murders (and later [[ImAHumanitarian cooks and eats]]) Cone simply because he beat him in a basketball match.
* DrugsAreBad: “Angels With Dirty Faces”
* ExactlyWhatItSaysOnTheTin: Half Hour of Power, although it's actually slightly shorter, with the 30 minutes length being padded out by three minutes of silence after the last song.
* FadingIntoTheNextSong: They use this a lot. "Grab the Devil by the Horns" to "Machine Gun", "Summer" to "32 Ways to Die" to "Second Chance for Max Headroom", "Dave's Possessed Hair" to "Ride the Chariot to the Devil", almost entire ''All Killer No Filler'', "Thanks for Nothing" to "Hyper-Insomnia-Para-Condroid" to "Billy Spleen", “Intro” to “No Reason” to "We're All to Blame", and all three parts of “A Dark Road Out of Hell”.
* FlippingTheBird: At concerts, Derick leads the audience in the "41 Salute," which consists of holding up four fingers on the left hand and the middle finger on the right.
* GenreRoulette: Mostly varieties of rock, but they've done PopPunk, Horror Punk, HardcorePunk, RapRock, EmoMusic, AlternativeRock and even ThrashMetal.
* GenreShift / NewSoundAlbum: See above.
* GratuitousFrench: "Ma Poubelle". Although the song is entirely in French, Deryck uses English accent.
* GreatestHitsAlbum: ‘’All the Good Shit’’
* HeavyMetal: They had an AlterEgoActing band named [[FakeBand Pain for Pleasure]], where they performed in wigs and costumes and used nicknames - Steve (who was lead vocalist here) was Pain, Deryck (drummer) was Gunner, Dave was Pleasure and Cone was Sniper. They recorded three songs under this monicker: Pain for Pleasure, Reign in Pain and WWVII Parts 1 & 2. They also appeared as this in two of their music videos: Fat Lip (where they performed their self-titled song) and We're All to Blame (where they were announced as next band to perform on Solid Gold). Incidentally, Deryck is shown as guitarist in both of those appearances, although he actually played drums in this band.[[note]]Dave is credited in the band as "the metal guy," as most of the metal influences in the songwriting came from him. All of the guitar solos and shredding riffs came and left with him.[[/note]]
* ImAHumanitarian: In one of their web videos, Basketball Butcher, after losing against Cone in basketball match, Steve kills him and then cooks him. Later, Deryck and Dave come in. They ask him what is for the dinner. Steve replies with "You!".
* IncrediblyLongNote: Dave has one near the end of [[Music/{{Nickelback}} “How You Remind Me”]].
* InkSuitActor: The band, in it's original incarnation, were animated into an episode of ''WesternAnimation/KingOfTheHill'' where they played a Christian rock band.
* InsultBackfire: [[Music/{{Oasis}} Noel Gallagher]] once called them "the worst band in the world". They liked it enough to use it as a slogan for a while.
* LighterAndSofter: While darker than All Killer No Filler, Underclass Hero was this to the album previous album Chuck and sounds closer to Does This Look Infected.
* MetalScream: Once again, “Mr. Amsterdam”
* MoodWhiplash: ''Chuck'' is especially made of this. Not only does it put relatively softer songs ("Some Say", "Pieces" and "Slipping Away") between fast and aggresive songs, but even some of the heavier songs on the album have slower, melodic parts such as on "We're All to Blame" (aggresive verses, calm choruses) or "88" (which has calmer first verse and the outro, but is otherwise fast and heavy).
* NobodyLovesTheBassist: Cone is the only one to not rap on both “Fat Lip” and “What We’re All About”.
* NonAppearingTitle: Sorted by albums, excluding some partial examples and istrumentals.
** ''Half Hour of Power'': "Machine Gun", "Summer" (also on ''All Killer, No Filler''), "Second Chance for Max Headroom" and "Dave's Possessed Hair".
** ''All Killer No Filler'': "Introduction to Destruction", "Fat Lip", "Crazy Amanda Bunkface" and "Heart Attack".
** ''Does This Look Infected?'': "The Hell Song", "A.N.I.C.", "No Brains", "Mr. Amsterdam", "Hyper-Insomnia-Para-Condriod", "Billy Spleen" and "Hooch",
** ''Chuck'': "Angels with Dirty Faces", "Welcome to Hell", "88", "Moron", "Noots" and "Subject to Change".
** ''Underclass Hero'': "Underclass Hero", "Speak of the Devil", "With Me", and "Confusion and Frustration in Modern Times".
** ''Screaming Bloody Murder'': "Screaming Bloody Murder", "Jessica Kill", "Crash" and "Exit Song",
* OdeToSobriety: "War," inspired by Deryck's stint in rehab for his alcoholism. While there, he realized he needed to set a goal for himself to get sober, that goal being continuing to perform. His mantra of "What am I fighting for?" became the song's refrain.
* PerishingAltRockVoice: In the outro to “Skumfuk”
* PowerBallad: “Slipping Away”, “Pieces”, “With Me”, and “What Am I To Say”
* ProtestSong: “Still Waiting”, “Underclass Hero”, and the majority of ‘’Chuck’’.
* PunBasedTitle: The band's name comes from the fact that they formed "some 41 days into the summer."
* PunkRock
* PutOnABus / TheBusCameBack: Dave Baksh.
* RapRock: Many of their earlier songs, especially "Fat Lip" and "What We're All About," as a holdover from Deryck's brief tenure in a rap group prior to the band forming. "The Fall and the Rise" from ''13 Voices'' has elements of this. They also collaborated with Ludacris for a rock version of "Get Back."
* RockTrio: During Underclass Hero era they officially consisted only of Deryck, Cone and Steve (Tom was a live member only and as such did not play on the album, nor did he appear in music videos). Screaming Bloody Murder was also recorded in three piece despite Tom Thacker already being a member of the band at that point (he did get a co-writing credit for title track, though).
* {{Rockumentary}}: ''Rocked: Sum 41 In Congo.'' Subverted in that it's not so much about the band and their music as it is their experience visiting the Democratic Republic of the Congo in Africa and getting caught in a deadly shootout. See "WarIsHell" for more.
* SpecialGuest: [[Music/{{Slayer}} Kerry King]] on [[Film/SpiderMan1 What We're All About]].
** Sum 41 themselves performed on Little Know It All by [[Music/TheStooges Iggy Pop]] and Get Back by Ludacris.
* StageName: Cone was born Jay [=McCaslin=]. Derick gave him the nickname in high school when he always saw Jay eating ice cream cones at lunch.
* StartMyOwn: Dave Baksh, who left to form Brown Brigade. Although he only recorded one album with that band, then it seemed to fade.
* StepUpToTheMicrophone: Aside from singing on Pain for Pleasure songs, Steve also rapped on Fat Lip, What We're All About and Thanks for Nothing (along with Deryck and in case of first two, Dave).
* StudioChatter: At the beginning of “We’re All to Blame”.
* SurprisinglyGentleSong: “Slipping Away”, “Pieces”, “With Me”, “What Am I To Say”, bits of “Happiness Machine”, and “Crash”
* TheSomethingSong: The Hell Song, Exit Song
* TitleTrack: ''Underclass Hero'', ''Screaming Bloody Murder'' and ''13 Voices''
* TrashTheSet: The end of Still Waiting video. Also in Walking Disaster.
* WarIsHell: After recording ''Does This Look Infected?,'' the band took a break from music to join War Child Canada (the Canadian equivalent of The Peace Core), which sent them to the Democratic Republic of the Congo in Africa to work with Congolese youths and witness the country's long-ongoing war firsthand. While there, they were caught in a deadly crossfire between rebel soldiers and government troops and wound up trapped in the remains of their hotel for two days until they and everyone trapped with them were rescued by a peacekeeper named Chuck Pelletier, who brought them safely home. Most of their following album, named ''Chuck'' in Pelletier's honor, was written to reflect on the experience.