The album was credited as the biggest pop debut of 2002. It was released to generally positive critical reviews, although Lavigne's songwriting received some negative comments. Let Go was 6x platinum in the United States. It also did extremely well in Canada, receiving a diamond certification from the Canadian Recording Industry Association, as well as reaching multi-platinum in many countries around the world, including the UK in which she became the youngest female solo artist to have a number-one album in the region.
As of May 2008, Let Go had sold over 17 million copies worldwide, becoming Lavigne's highest-selling album to date. According to Billboard Magazine the album was the number 21 top-selling album of the decade. A Rolling Stone readers poll named Let Go as the fourth best album of the 2000s.