"Shake It Out" is a song by English indie rock band Florence and the Machine, released as the first official single from their second studio album, Ceremonials (2011). It was written by Florence Welch and Paul Epworth, while production was handled by Epworth. The song was digitally released in Australia on 14 September 2011, and it was available in the United States on 19 October. It had its radio debut on XFM on 14 September 2011 in the United Kingdom. Welch revealed that the song was written within an hour and according to her it talked about shaking the regrets and the things that were haunting her.

Florence and the Machine are an English indie rock band that formed in London in 2007, consisting of lead vocalist Florence Welch, keyboardist Isabella Summers, guitarist Rob Ackroyd, harpist Tom Monger, and a collaboration of other musicians. The band's music has received acclaim across the media, especially from the BBC, which played a large part in their rise to prominence by promoting Florence and the Machine as part of BBC Music Introducing. At the 2009 Brit Awards they received the Brit Awards "Critics' Choice" award. The band's music is renowned for its dramatic, eccentric production and Welch's powerful vocals.