"Sk8er Boi" (/ˈskeɪtərbɔɪ/, "skater boy") is a song by Avril Lavigne, and is the second single from her debut album, Let Go (2002). It was written by Avril Lavigne and The Matrix (Scott Spock, Lauren Christy, and Graham Edwards), and produced by The Matrix. Released in 2002, the single reached number ten on the United States Billboard Hot 100 (becoming Lavigne's second top ten single there), number eight in the United Kingdom, number three in Australia, number thirteen in Canada and number one in Spain, becoming one of her most successful songs to date.
The music video, directed by Francis Lawrence, centers around an impromptu concert held by Lavigne in a Los Angeles street intersection. It begins by showing multiple people of Lavigne's band promoting the concert in advance via graffiti, flyers, email and posters. Lavigne and her band arrive at the location and begin performing on the roof of their cars; a crowd quickly gathers. Towards the end of the song, police cars and a helicopter arrive to disperse the crowd, while Lavigne uses her guitar to break the car windscreen. Lavigne then throws the guitar onto the road and looks up at the helicopter, where a shot was taken for the single's artwork.
The video was considered the third 'Best music video of the decade' in the UK by BT Vision.
In a review for the album Let Go, Christina Saraceno of Allmusic called "Sk8er Boi" a "terrific power pop bounce", highlighting the song as a "track pick". However she noted the lyrics show Lavigne's shortcomings as a writer. John Perry of Blender magazine labelled the lyrics to "Sk8er Boi" as "endearingly naive". By contrast, a poll on the website magpiemusic.com voted the song's lines "He was a boy, she was a girl. Can I make it any more obvious?" at fourth place, in its list of "Worst Lyrics of All Time". 
In an AOL Radio listener's poll, "Sk8er Boi" was voted Lavigne's fourth best song.
As of July 2013, Sk8er Boi had sold 755,000 digital copies in the US.
Cover versions and appearances in other media