"The Phantom of the Opera" is a song from the stage musical of the same name. It was composed by Andrew Lloyd Webber, with lyrics written by Charles Hart and Richard Stilgoe, and additional lyrics by Mike Batt. The song was originally recorded by Sarah Brightman and Steve Harley, which became a UK hit single in 1986, prior to the musical. In its theatrical debut, it was sung by Brightman and Michael Crawford in their roles as Christine Daaé and the Phantom.

The song is performed in Act I after the song "Angel of Music" (The Mirror) and before "The Music of the Night" (and is reprised in Act Two at the end of the song "Notes/Twisted Every Way"). It takes place as the Phantom escorts Christine by boat to his lair beneath the Opera Garnier. It is sung as a duet by Christine and the Phantom. At the end of the song, Christine sings her highest note in the show, an E6. In different shows, Sarah Brightman sings this song in different duets with other performers, Antonio Banderas, Chris Thompson, Alessandro Safina, Mario Frangoulis, Colm Wilkinson, Anthony Warlow, John Owen-Jones, Peter Jöback and Erkan Aki.