"Shake It Off" is a song recorded by American singer-songwriter Taylor Swift. Written by Swift and its producers Max Martin and Shellback, "Shake It Off" is an uptempo dance-pop song featuring a saxophone line in its instrumental. The lyrics are about Swift's indifference to her detractors and their negative comments on her image, inspired by the media scrutiny that she had experienced. It was the lead single from her fifth studio album, 1989, which Swift marketed as her first pop album that eschews the country-pop sound of her previous repertoire. The song was released for digital download worldwide on August 18, 2014, by Big Machine Records.

Contemporary critics received "Shake It Off" with moderate reviews. They found the song's dance-pop production catchy but lamented that the lyrics were not up to par with Swift's traditional vivid songwriting. Retrospectively, critics have considered "Shake It Off" an effective opener for the 1989 era, which transformed Swift's sound and image from a country singer-songwriter to a pop star. The song featured on 2010s-decade-end lists by NME and Consequence of Sound. The single became Swift's biggest chart success in the United States, spending 50 weeks–including four weeks at number one–on the Billboard Hot 100, and receiving a diamond certification from the Recording Industry Association of America. "Shake It Off" also topped charts in Australia, Canada, Hungary, New Zealand, and Poland.

The single was supported by a music video directed by Mark Romanek. The video, in which Swift portrays a clumsy person attempting to practice several dance moves without success, attracted accusations of cultural appropriation for featuring dance routines associated with people of color such as twerking. To promote the song, Swift performed live on televised events including the MTV Video Music Awards and the iHeartRadio Music Festival. She included "Shake It Off" on the setlists for two of her world tours, the 1989 World Tour and Reputation Stadium Tour. "Shake It Off" has received numerous accolades, including Favorite Song at the 2015 People's Choice Awards and three Grammy nominations at the 2015 Grammy Awards.