Claim: Avril Lavigne wrote the song Complicated.

`` Complicated '' is the debut single by Canadian singer-songwriter Avril Lavigne , released in 2002 from her debut album , Let Go . It was written by Lavigne and The Matrix -LRB- Scott Spock , Lauren Christy , and Graham Edwards -RRB- , and produced by The Matrix . The single reached number one in Australia -LRB- for six weeks -RRB- , New Zealand and Mexico -LRB- for nine weeks -RRB- , number two on the Billboard Hot 100 , behind `` Hot in Herre '' by Nelly and number three in the United Kingdom . Based on its chart performance , the song is Lavigne 's second most successful single -LRB- only behind her 2007 single `` Girlfriend '' -RRB- and was one of the most successful releases of 2002 . Lavigne broke a record set by Natalie Imbruglia 's `` Torn '' when `` Complicated '' held the number one spot on the Adult Top 40 chart for 16 weeks in a row . `` Complicated '' was nominated for two Grammy Awards for Song of the Year and Best Female Pop Vocal Performance .