"Secret" is a song by American singer Madonna from her sixth studio album, Bedtime Stories (1994). It was released by Maverick Records on September 26, 1994, as the lead single from the album. The singer originally recorded the song as a demo with producer Shep Pettibone. However, Dallas Austin replaced Pettibone's role as the producer and reworked its composition, earning him a writing credit alongside Madonna. It was a departure from Madonna's previous musical style, since up to that point in her career, her music had mostly consisted of big-sounding dance tracks and melodic ballads. "Secret" combined the pop and R&B genres with instrumentation from an acoustic guitar, drums and strings, while lyrically talking about a lover having a secret.

The song was released accompanied by eight different remixes by DJ Junior Vasquez, who re-used Madonna's vocals, but changed the composition of the track completely. Unusual for a singer in the mid-1990s, Madonna talked about the new single on the Internet, leaving an audio message for her fans as well as a snippet of the song. "Secret" received favorable reviews from music critics, who praised Madonna's vocal delivery and its mid-tempo R&B groove, deeming it seductive and soulful. The song was also a commercial success. In the United States, it peaked at number three on the Billboard Hot 100 and was certified gold by the Recording Industry Association of America (RIAA). In the United Kingdom, it reached a peak of number five, becoming her record-breaking 35th consecutive top-ten single on the UK Singles Chart. Elsewhere, it reached number one in Canada, Finland, and Switzerland, and the top five in Australia, Denmark, France, New Zealand and Spain.

With the single's cover art and its accompanying music video, Madonna ushered in another image change, inspired by the look of Hollywood actress Jean Harlow. The black and white video was directed by photographer Melodie McDaniel, who was chosen by the singer due to McDaniel's previous short films. It features Madonna as a singer in a nightclub in Harlem, New York City. Interspersed with scenes of daily life in the neighborhood, the video ends with Madonna uniting with her lover and their supposed child. The video sparked academic discussions about what might constitute the lyrical secret of the song.

Madonna performed "Secret" on tour for the first time during her 2001 Drowned World Tour. It was later performed at the Houston stop of her Sticky and Sweet Tour in November 2008 as a fan request, and seven years later on some shows of the Rebel Heart Tour.