"Unchained Melody" is a 1955 song with music by Alex North and lyrics by Hy Zaret. North wrote the music as a theme for the prison film Unchained (1955), hence the song title. Todd Duncan sang the vocals for the film soundtrack. It has since become a standard and one of the most recorded songs of the 20th century, most notably by the Righteous Brothers in 1965. According to the song's publishing administrator, over 1,500 recordings of "Unchained Melody" have been made by more than 670 artists, in multiple languages.

In 1955, three versions of the song (by Les Baxter, Al Hibbler, and Roy Hamilton) charted in the Billboard top 10 in the United States, and four versions (by Al Hibbler, Les Baxter, Jimmy Young, and Liberace) appeared in the top 20 in the United Kingdom simultaneously, a record for any song. The song continued to chart in the 21st century, and it was the only song to reach number one with four different recordings in the United Kingdom until it was joined by Band Aid 30's "Do They Know It's Christmas?" in 2014.

Of the hundreds of recordings made, the Righteous Brothers' version, with a solo by Bobby Hatfield, became the jukebox standard after its release. Hatfield changed the melody in the final verse and many subsequent covers of the song are based on his version. The Righteous Brothers recording achieved a second round of great popularity when featured in the film Ghost in 1990. In 2004, it was number 27 on AFI's 100 Years...100 Songs survey of top tunes in American cinema.