Avril Lavigne wrote the song Complicated.
Avril Lavigne . Her breakthrough single , `` Complicated '' , peaked at number 1 in many countries around the world , as did the album Let Go . Complicated (Avril Lavigne song) . It was written by Lavigne and The Matrix ( Scott Spock , Lauren Christy , and Graham Edwards ) , and produced by The Matrix . `` Complicated '' is a song by Barbadian recording artist Rihanna from her fifth studio album Loud ( 2010 ) .