"Fat Lip" is a song by the Canadian rock band Sum 41, released in 2001 as part of their album All Killer No Filler. The song blends elements of punk rock and hip-hop, showcasing the band's energetic style and catchy melodies. Its lyrics express themes of rebellion and youthful defiance, resonating with many listeners. The track became a commercial success, reaching high positions on various music charts worldwide. Its memorable chorus and dynamic instrumentation contributed to its popularity, making "Fat Lip" one of Sum 41's signature songs. The song's music video further amplified its reach, featuring a fun and chaotic party atmosphere.