Goodbye Lullaby is the fourth studio album by Canadian singer-songwriter Avril Lavigne. It was released on 2 March 2011, being her last release under RCA Records. The album was released four years after the release of her earlier album The Best Damn Thing (2007), being pushed back several times. Recording sessions began in November 2008, and took place over a period of almost two years, concluding in October 2010. "Goodbye Lullaby" themes deal mainly with heartbreak, exploring what it means to push through the tough times and emerge stronger for it, containing mainly stripped down instruments, such as the piano and acoustic guitar. Lavigne co-wrote every track on the album, with herself producing two songs alone. She also worked with producers Max Martin, Shellback, Butch Walker and her former husband Deryck Whibley.

Upon its release, Goodbye Lullaby received generally mixed reviews from music critics, with some calling it "one of her most personal and introspective albums to date", while many criticized it for being "unfun, affected and an ineffectual attempt at a serious pop record." The album debuted inside the top five in over 15 countries such as the United States and Canada, topping the charts in over eight countries, such as Australia, Greece, Hong Kong and Japan.

Three singles were released from the album. The album's lead single, "What the Hell", was released on 7 January 2011, and achieved worldwide chart success; reaching the top twenty in the United States and United Kingdom, the top ten in Europe and Australia and the top five in Asia. The following singles, "Smile" and "Wish You Were Here", had moderate chart success worldwide. The album also includes an extended version of the soundtrack single for the 2010 film Alice in Wonderland, titled "Alice". Lavigne promoted the album with a series of live performances, including her The Black Star Tour (2011).