"I'm Not in Love" is a song by British group 10cc, written by band members Eric Stewart and Graham Gouldman. It is known for its innovative and distinctive backing track, composed mostly of the band's multitracked vocals. Released in the UK in May 1975 as the second single from the band's third album, The Original Soundtrack, it became the second of the group's three number-one singles in the UK between 1973 and 1978, topping the UK Singles Chart for two weeks. "I'm Not in Love" became the band's breakthrough hit outside the United Kingdom, topping the charts in Canada and the Republic of Ireland as well as peaking within the top ten of the charts in several other countries, including Australia, Germany, New Zealand, Norway and the United States.

Written mostly by Stewart as a riposte to his wife's declaration that he did not tell her often enough that he loved her, "I'm Not in Love" was originally conceived as a bossa nova song played on guitars, but the other two members of the band, Kevin Godley and Lol Creme, disliked the track and it was abandoned. However, after hearing members of their staff continue to sing the melody around their studio, Stewart persuaded the group to give the song another chance, to which Godley replied that for the song to work it needed to be radically changed, and suggested that the band should try to create a new version using just voices.