"One Man in My Heart" is a song by English synth-pop band the Human League, written by Neil Sutton and Philip Oakey. It was released as the second single from the band's seventh album, Octopus (1995), on 6 March 1995 by East West Records. A ballad, the song differs from all previous Human League tracks as the lead vocal is performed by band member Susan Ann Sulley, with spoken-word refrains from Oakey and contrasting backing from the third member, Joanne Catherall. The song received positive reviews from music critics and peaked at number 13 on the UK Singles Chart, spending eight weeks in the top 100. Its music video was directed by Andy Morahan. In 2001, The Guardian newspaper named "One Man in My Heart" one of the best love songs of the 1990s.^[2]

Dave Thompson of AllMusic said "One Man in My Heart" "could have been a total throwaway, a gloopy little love song without a single redeeming quality, beloved by grannies and tweenies, gag-inducing for those outside those age parameters. But the band obviously gave the number time and attention, and thus ensured that it can't be so easily dismissed." He added that "the group produced a love song unlike virtually all typical pop fodder."^[3] Larry Flick from Billboard were also highly favourable, writing that "this sophomore single from the act's comeback album Octopus needs no apologies for its innocent composition. It is a beautiful ballad that should set top 40 afire."^[4] Steve Baltin from Cash Box commented, "Given that it's impossible to write off the trio, even though this song also seems stuck in a time warp. While other bands from the era, specifically Duran Duran and Adam Ant, have reinvented their sound, the Human League have actually regressed, being more keyboard based than in their initial run. Still, there is something cute about the tune."^[5]

Anderson Jones from Entertainment Weekly described it as "melodramatic synth-pop-orchestrated".^[6] Music writer and columnist James Masterton noted that it is unusually featuring Catherall and Sulley on vocals completely on their own. "The result is a tender woman's ballad to which the expression 'lovely' could almost be said to have been coined."^[7] Jennifer Nine from Melody Maker wrote, "More enticing craftmanship sparkles in the music-box minuet of "One Man in My Heart": tiny, shimmering, and ooh-la-la-luscious as Saint Etienne without the swotty paperwork."^[8] Another Melody Maker editor, Dave Simpson, said, "'One Man' is a straight(ish) love song, catchy as crabs and delivered with the slight awkwardness critics often mistake for irony."^[9] A reviewer from Music Week gave it four out of five, describing it as "a gorgeous semi-ballad that could be ABBA if you didn't know better."^[10] Criticism of Susan Ann Sulley's vocals was that she was too technically proficient making her sound "bland"; one critic declared that he missed "the rough edges of the girl plucked from the Sheffield dance floor".^[11]

The accompanying music video for "One Man in My Heart" has a similar cinematography style to the video for the previous single "Tell Me When" and had the same director, Andy Morahan. It is set in a Parisian cafe and principally features (for this song) lead vocalist Susan Ann Sulley sat on her own having a coffee while singing to herself; whilst watching the other customers. Fellow band members Philip Oakey and Joanne Catherall are seated elsewhere in the cafe and the camera pans to them for their backing vocals and Oakey's incidental spoken words.^[12] The video received considerable play on VH1.