"Not in Love" is the title of two covers by the Canadian electronic music duo Crystal Castles, both renditions of the 1983 song of the same name by the Canadian rock band Platinum Blonde. The first version appeared on the duo's second studio album, Crystal Castles (2010), while a second version featuring Robert Smith of the Cure was digitally released as a non-album single on October 26, 2010. Crystal Castles' Ethan Kath recorded his own vocals for their first version of "Not in Love"; following the Crystal Castles' release, Smith asked if he could remix a song on the album, ultimately resulting in the second version of "Not in Love".

Critics found the first version of "Not in Love", a synth-pop song, to be calmer than Smith's version, which they felt had more impactful beats and synths. Although the album version was generally seen as unexciting, the version with Smith was praised by critics, especially for its vocals. It was named one of the best songs of 2010 by multiple publications. It appeared in the main charts of Australia, Denmark, Scotland, and the United Kingdom, and was certified gold in Canada by Music Canada.

"Not in Love" is a 1983 song by Platinum Blonde. Crystal Castles re-recorded it for Crystal Castles (2010), which, according to a press release, was recorded at "an Icelandic church, a Canadian cabin, and a Detroit garage". Another press release mentioned that Crystal Castles opened for the Cure at London's The O2 Arena in February 2009; this was the first time they met. Crystal Castles member Ethan Kath recorded his own vocals for "Not in Love" as "a scratch demo"; he did not intend for them to be final, but they did end up on the album. Following the album's release, Robert Smith of the Cure asked if he could remix a song on Crystal Castles. Kath suggested that Smith replace his vocals in "Not In Love" instead. Smith recorded "raw demo vocals" for the song, but when the band listened to the result they became attached to the way the demo was sung and decided to keep the song as it was, and canceled their plans to record Smith again in a studio.

The Smith version of "Not in Love" was announced on October 25, 2010, and officially released as a single two days later. It was planned to be released on December 6 in the United Kingdom via Fiction Records, with the B-sides containing acoustic demos of "Celestica" and "Suffocation", but the UK release never happened. An accompanying music video directed by Nic Brown was released in January 2011. The song was featured in the video game FIFA 12 (2011).

Crystal Castles' first cover of "Not in Love" was characterized as synth-pop by Heather Phares of AllMusic. Pitchfork's Mark Richardson said that this version was filled with digital noise and heavy distortion, although Mark Pytlik wrote to the same website that it is "much tamer" when compared to the version with Smith. Cameron Scheetz of The A.V. Club wrote that Kath's "distant, distorted vocals" on that version provided a ghostly feel to the lyrics. An NME writer said that "[t]here's an urgency to the keyboards that crescendos into a wall of sound that wraps around you like a blanket".

Regarding the version with Smith, Scheetz said that it brought his emotive vocals to the forefront and enhanced the song's "throbbing" beat, adding that, in the chorus, "the already propulsive synths become unavoidably sweeping". Beats Per Minute's Philip Cosores said that this version's chorus has a heavier mix. Pytlik declared that Kath's "storming synth squalls" provide the perfect contrast to Smith's "precarious and insecure delivery". Larry Fitzmaurice of Pitchfork said that this version has a stronger structure and powerful synths with an anthemic intensity.

The version on the Crystal Castles album was generally considered unexciting by critics. Drowned in Sound's James Lawrenson said that it could be considered "filler" and "dropped as a B-side", while Cosores of Beats Per Minute described it as "pretty pedestrian". Emily Bick of The Quietus wrote that the song "shifts towards discomfort, disillusion, despair"; conversely, Justin Jacobs of Paste described it as "pretty" and that sounding "the way twinkling Christmas lights look". Pytlik of Pitchfork said that the track "barely seemed to make a dent" when Crystal Castles was released.

Pitchfork named the re-recording with Smith "Best New Track", with Richardson saying that Smith "elevates" Crystal Castles' first version, balancing nostalgia and the immediacy of life. Fact staff wrote that it is "as satisfying as you could have hoped for". Pitchfork's Ryan Dombal wrote "Smith's voice is loud and clear on the track", making it one of Crystal Castles' catchiest works. Larry Fitzmaurice wrote to the same website that the song is "massive", evoking chills, and that, while the song is a cover, its "high-definition angst" felt unique to the band. He also said that this was one of the best performances by Smith until that time.

Scheetz wrote that Smith's emotional vulnerability reveals "the tender longing[s] beneath Crystal Castles' cool, icy facade". Brandon Stosuy of Stereogum said that the cover "sounds like the best thing the Cure put together in ages", while providing a new perspective on the "saturated, blasted goth-noise prettiness" of Crystal Castles. Slant Magazine staff said that "[t]he crunchy production combined with Smith's familiar pangs is heart-wrenching and nothing short of blisteringly gorgeous". Molly Beauchemin from Pitchfork described the song as having an explosive, "life-affirming" chorus that transitions into Kath's tender interludes with "triumphant precision", calling it one of Crystal Castles' "finest, most cathartic ballads". A DIY writer described the song as the most destined for festival stages and the purest of any Crystal Castles release, adding that it was one of the best covers of the 2010s and "a crazed re-creation of a song that looked to be dead and buried".

"Not in Love" was ranked as one of the 20 best songs of 2010 by the likes of Beats Per Minute, Pitchfork, and Slant Magazine. In 2014, Pitchfork considered it among the best songs of the decade until then. In 2022, Rolling Stone named the track as one of the best gothic songs of all time.

Accolades for "Not in Love"

Publication	List	Rank	Ref.
BBC Radio 6 Music	Top 40 of 2010 (shortlist)	—
Beats Per Minute	The top 50 tracks of 2010	18
Fact	The 100 best tracks of 2010	39
Pazz & Jop	2010 singles poll	22
Pitchfork	The top 100 tracks of 2010	15
	The 200 best tracks of the decade so far (2010–2014)	34
PopMatters	The 60 best songs of 2010	47
Rolling Stone	The 50 best goth songs of all time (2022)	20
Slant Magazine	The 25 best singles of 2010	13

In Australia, "Not in Love" peaked at 90 in the ARIA Charts. In Belgium, it charted at the Ultratip Bubbling Under Flanders at number 3 and on the Ultratop 50 Wallonia at 43. In Canada, the song entered Billboard's Canada Rock at 39 and was certified gold by Music Canada, with 40,000 certified units. It appeared in Denmark's Tracklisten at 31. In Mexico, it peaked at 18 on Billboard's Mexico Ingles Airplay. "Not in Love" appeared on the Official Charts Company's Scottish Singles Chart at 57 and the UK Singles Chart at 53. In the United States, it entered the two Billboard charts of Alternative Airplay at 24 and Dance/Electronic Digital Song Sales at 19.

Digital single

1. "Not in Love" (radio version) – 3:49
2. "Not in Love" (Robert Smith mix) – 3:49

Adapted from Spotify; applies to both the radio version and the Robert Smith mix.

• Alice Glass  – performer, writer
• Ethan Kath  – performer, writer, producer
• Robert Smith  – performer, writer
• Mark Holmes  – writer
• Jacknife Lee  – producer
• Paul Epworth  – producer

Chart performance for "Not in Love"

Chart (2010)	Peak position
Australia (ARIA)	90
Belgium (Ultratip Bubbling Under Flanders)	3
Belgium (Ultratop 50 Wallonia)	43
Canada Rock (Billboard)	39
Denmark (Tracklisten)	31
Mexico Ingles Airplay (Billboard)	18
Scotland (OCC)	57
UK Singles (OCC)	54
US Alternative Airplay (Billboard)	24
US Dance/Electronic Digital Song Sales (Billboard)	19

Certifications for "Not in Love"

Region	Certification	Certified units/sales
Canada (Music Canada)	Gold	40,000
Sales+streaming figures based on certification alone.

• Not In Love ft. Robert Smith (YouTube)