It was a hit across Europe, becoming a number-one single in at least 13 countries and reaching number two in Germany, Sweden and the United Kingdom.

"[8] The female vocal on the track, meanwhile, was a stock sample released on the Zero-G sample compilation CD "Datafile 1" (tracks 62–64), which was produced in 1991 by Zero-G co-founder and Jack 'N' Chill member Ed Stratton, aka Man Machine, and was aimed at dance producers, DJs, programmers and artists.

[21] In Sweden, Germany and the United Kingdom, it peaked at number two, being kept off the top spot by Snow's "Informer", Ace of Base's "All That She Wants" and Gabrielle's "Dreams".

[32] Upon the release, Larry Flick from Billboard described the song as a "glorious pop/house ditty", and stated that "wildly catchy chorus is complemented by a slick, synth-happy arrangement.

"[33] Milo Miles from The Boston Globe wrote, "He pours such delicacy and anguish into the short phrases they become loud whispers that stay in the ear.

"[34] Student newspaper Columbia Daily Spectator said it "will transport you instantly to the golden age of house music.

"[35] Jim Farber from Daily News noted that "What Is Love" "uses every sound it has to punch the beat: a stabbing synth line, a tense bass, an uplifting lead vocal and an encouragingly frantic female voice to back it up.

"[37] In his weekly UK chart commentary, James Masterton stated that the song "is undoubtedly one of the best soul releases of the year.

"[38] Pan-European magazine Music & Media remarked that it has a "fast house beat augmented by Nestor Haddaway's deeply soulful vocals.

"[39] Wendi Cermak from The Network Forty described the track as "splendiferous", and noted that "the eargasmic synth stabs in the extended mix are pulling even odds in Vegas for dance-floor-filling capability and the edit screams for radio airplay..."[40] Luke Turner from The Quietus felt that "What Is Love" "bangs because it manages to be two things—a terrific soul tune but also rather stern as well, with infernally naggy synth lines and drilled repetition in the rhythms.

"[41] Tony Cross from Smash Hits gave it four out of five, writing, "Haddaway's attempt at producing something along the lines of Seal's "Crazy" hasn't quite been pulled off, but this foot-friendly dance track is still stonking dance-floor stuff.

"[42] Another Smash Hits editor, Pete Stanton, declared it as "a disco-dancing, ass-grooving, tum-churning corker of a song.

NME ranked "What Is Love" number two in their list of "Top Five Euro-Hits of All Time" in December 1993,[45] writing, "Haddaway takes one of the fundamental questions of man's existence and puts it to a stomping disco beat.

Vain", "Rhythm Is a Dancer" and "What Is Love" as modern classics, "butt-shaking Wagnerian disco monsters.

"[48] Mike Wood from Idolator featured it in their list of "The 50 Best Pop Singles of 1994" in 2014, calling it a "catchy" anthem, that "permeated our collective consciousness given the heavily-repeated airplay".

In 2016, Belgian DJ Lost Frequencies released a cover titled "What Is Love 2016", as a single from his debut album Less Is More.

In the late 1990s, the song was featured in the popular, recurring Saturday Night Live "Roxbury Guys" sketches, in which the characters Steve and Doug Butabi (played by Will Ferrell and Chris Kattan respectively) would wildly bob their heads to the track as they went out nightclubbing and had misadventures.