Under My Skin is the second studio album by Canadian singer-songwriter Avril Lavigne. It was released firstly in Europe on May 21, 2004 then it followed the release in the rest of the world on May 25, 2004 by Arista Records and RCA Records. Lavigne wrote most of the album with singer-songwriter Chantal Kreviazuk, who invited her to a Malibu in-house recording studio shared by Kreviazuk and her husband Raine Maida, where Lavigne recorded many of the songs. The album was produced by Maida, Don Gilmore, and Butch Walker. It is Lavigne's second and final studio album to be released on Arista, following Let Go (2002). It was also her first album for RCA.

Avril Ramona Lavigne is a Canadian singer-songwriter. She is considered a key musician in the development of pop-punk music, as she paved the way for female-driven, punk-influenced pop music in the early 2000s. Her accolades include eight Grammy Award nominations, among others.