"Hung Up" is a song by American singer Madonna from her tenth studio album Confessions on a Dance Floor (2005). Initially used in a number of television advertisements and serials, the song was released as the album's lead single on October 17, 2005. Written and produced by Madonna in collaboration with Stuart Price, "Hung Up" prominently features a sample from the instrumental introduction to ABBA's single "Gimme! Gimme! Gimme! (A Man After Midnight)", for which Madonna personally sought permission from its songwriters, Benny Andersson and Björn Ulvaeus. This is thought to be only the second time Andersson and Ulvaeus have given permission to sample one of their songs, following Fugees song "Rumble in the Jungle" for the soundtrack of the film When We Were Kings.

Musically, the song is influenced by pop music from the 1980s, with a chugging groove and chorus and a background element of a ticking clock that suggests the fear of wasting time. Lyrically the song is written as a traditional dance number about a strong, independent woman who has relationship troubles. "Hung Up" received critical praise from reviewers, who considered it among Madonna's best dance tracks and believed that the track would restore her popularity, which had diminished following the release of her 2003 album American Life. "Hung Up" became a global commercial success, peaking atop the charts of 41 countries and earning a place in the Guinness Book of World Records. It was Madonna's 36th top 10 single on the Billboard Hot 100, tying her with Elvis Presley as the artist with most top ten entries. It also became the most successful dance song of the decade in the United States. "Hung Up" has sold over five million copies worldwide.

The music video is a tribute to John Travolta and his movies, and to dancing in general. Directed by Johan Renck, the clip starts with Madonna clad in a pink leotard dancing alone in a ballet studio and concludes at a gaming parlor where she dances with her backup troupe. Interspersed are scenes of people displaying their dancing skills in a variety of settings, including a Los Angeles residential neighborhood, a small restaurant and the London Underground. Madonna has performed the song in a number of live appearances, including as the final number of 2006's Confessions Tour, a heavy metal-inspired arrangement in the 2008 leg of the Sticky & Sweet Tour, and 2012's The MDNA Tour, where the singer performed the song while slacklining.