"Just Dance" is the debut single by American recording artist Lady Gaga. Written by Gaga, RedOne and Akon (who also provides additional vocals) and produced by RedOne, the song features labelmate Colby O'Donis. It was released in 2008 as the lead single from Gaga's debut album, The Fame. The song was written by Gaga in ten minutes as "a happy record". An uptempo dance song, "Just Dance" also has influences of R&B and lyrically speaks about being intoxicated at a club.

The song has been critically appreciated with reviewers complimenting its club anthem-like nature and the synth pop associated with it. The song has also achieved commercial success by topping charts in the United States, Australia, Canada, the Republic of Ireland, the Netherlands and the United Kingdom, as well as reaching the top ten in many other countries. In the United States, "Just Dance" was a sleeper hit, spending almost five months on the Hot 100 before finally reaching the summit of the chart in January of 2009. It scored the third-biggest single-week sum of all time selling 419,000 downloads in just one week and went to become the second best-selling digital song of all time.

The music video of the song portrayed Lady Gaga appearing in a party where she plays the song, prompting party-goers to start dancing in enjoyment. Gaga compared her experience of shooting the video with being on a Martin Scorsese set. "Just Dance" was performed by Gaga in a number of live appearances including her first headlining The Fame Ball Tour and the second worldwide tour Monster Ball. In 2009, the song received a Grammy nomination in the Best Dance Recording category but lost to electronic duo Daft Punk for their song "Harder, Better, Faster, Stronger".

"Just Dance" is written by Gaga and Akon with co-writing by RedOne who also produced the track. In an interview with Heat magazineGaga explained her inspiration for writing the song. She said,

"I was very hungover. I wrote the song in about 10 minutes with [producer] RedOne. And it was my first time being in a Hollywood studio. Very pristine, big huge room with giant speakers."

Gaga wrote "Just Dance" during January 2008 and according to her it was "hard work and a lot of people didn't believe in it at first". In an interview with Contactmusic.com Gaga explained that "Just Dance" is a happy record and is supposed to be appreciated by people going through rough times like losing jobs and homes etc. Gaga further explained with Artistdirect.com that she wanted to write a beautiful record with "Just Dance". Being asked the reason for which "Just Dance" has become popular, Gaga said that she thought,

"Everyone is looking for a song that really speaks to the joy in our souls and in our hearts and having a good time. It's just one of those records. It feels really good, and when you listen to it, it makes you feel good inside. It's as simple as that. I don't think it's rocket science when it comes to the heart. I think it's a heart theme song."

In March 2010 the song was released as downloadable content for the music-based videogame series Rock Band, along side "Poker Face", "Monster" and "Bad Romance" as part of "Lady Gaga Pack 01".

"Just Dance" is an uptempo dance song. The song combines synths of clipped marching beats, sawing electronics and contains mild R&B infused beats. The song is set in compound time with a moderate beat rate of 124 beats per minute. It is written in the key of C minor. Gaga's vocal spans the two octaves of G ₃to C ₅. The song begins with a fast tempo following by the synth arrangement and Gaga uttering "RedOne". The song goes into the same tempo during the chorus with Gaga's vocals spanning from B ₃to C ♯ . The chords are arranged in the progression of F—Am—C—G—D—F—Am—C—G—D—F. Colby O'Donis sings the interlude in the same range as Gaga. An R&B influenced interlude is sung by Gaga, after which the chorus is repeated with Colby providing backup vocals and the marching beats. The song ends with an echoing of the word "dance".

Lyrically, "Just Dance" throws a partial tongue-in-cheek perspective with lyrics like "What's going on on the floor? / I love this record, baby but I can't see straight anymore". The lyrics deal with being completely intoxicated at a party. The opening lyric "A RedOne" has often been misinterpreted as "red wine" but in actuality is a reference to producer RedOne.

The song has received generally positive reviews. Matthew Chisling of Allmusic described the song as galactic and compared it to "Money Honey", another track from her album. Alex Petridis of The Guardiancalled it a "beguilingly compulsive tale of pulling a drug-induced whitey, with a combination of clipped marching beats, sawing electronics and mild R&B flavour that bears a vague resemblance to Nelly Furtado's "Maneater". Ben Norman of About.com said that the song "opens the album like a valkyrie leading the charge [...] riding triumphant ahead of her army. If you don't know this song, use your browser. I won't waste time explaining what it sounds like." However he also noted that the song is not groundbreaking and compared it to the works of Rihanna, Chris Brown and Pussycat Dolls. Bill Lamb from About.com called the song tame but catchy enough for Gaga to be noticed by mainstream. He also added that "'Just Dance' has strong energy and features Lady GaGa's striking voice, but it ultimately adds up to rather bland dance-pop." Colby O' Donis' smooth vocals were also complimented. Evan Sawdey of PopMatters.com said that "Just Dance" is an intensely catchy single and is an excellent indicator of what the album was all about. Ben Hogwood of MusicOMH.compraised the song saying, "You won't get many more catchy party odes than the chart topping Just Dance this year, a polished gem set to lodge in your head for the next few weeks." Freedom lu Lac of The Washington Postdescribed the song to be "filled with mindlessly frothy synth-pop that matches low-grade dance grooves with GaGa's icy, almost disembodied vocals about dancing bliss". Lynn Saxberg from The Ottawa Citizenwhile reviewing Gaga's The Fame Ball Tour, called the song a perfect sing-along club anthem. Sal Cinquemani from Slant Magazine wrote that the song resembles the "desperate train wreck you're likely to encounter getting wasted at any dive on the L.E.S. at four in the morning" as is emphasized by the lyrics. Talia Kranes from BBC called the song irresistible and said that "the catchiness of her songs is sure to cement her place in the list of pop idols". However she mistakenly wrote the name of the song as "Let's Dance".

"Just Dance" was a club-hit in United States peaking at number two on both the Hot Dance Airplay and Hot Dance Club Play charts during the summer of 2008. The song entered the Hot 100 chart at seventy-six on August 16, 2008. It rose to number two on the Hot 100, after selling 419,000 in downloads as per the issue dated January 10, 2009. In the same issue, the song rose to number one on the Pop 100. The next week, the song finally rose to number one on the Hot 100. The single took twenty-two weeks to hit the top spot, which is the second-longest climb to number one since Creed's "With Arms Wide Open" took twenty-seven weeks before finally reaching number one in November 2000. The song also appeared on the Hot R&B/Hip-Hop Songs chart where it peaked at seventy-two. On March 12, 2009, the single was certified three times platinum by the Recording Industry Association of America (RIAA) for net sales of three million. The song has sold over five million downloads in the United States to date, becoming the second song to reach the five million mark in paid downloads.

The track debuted at number thirty-four on the ARIA Singles Chart on July 21, 2008, and moved up to seventeen the next week becoming the chart's "greatest gainer". On the issue dated September 15, 2008, the track topped the chart for one week before being replaced by Pink's single "So What". It has since been certified three times platinum by the Australian Recording Industry Association (ARIA) with sales of over 210,000 copies. In Canada, the song debuted at number ninety-seven on the Canadian Hot 100 for the issue dated June 7, 2008.. It reached the peak for the issue dated August 23, 2008 and was on the top for five consecutive weeks. The song was certified six times platinum by the Canadian Recording Industry Association (CRIA) in June 2009 for sales of 240,000 in paid digital downloads.

In Ireland, the song debuted at number eleven on the issue dated January 2, 2009. On the issue dated January 15, 2009 it peaked the chart. The single debuted on the New Zealand charts at number nineteen in the same week it appeared in the Australian chart. It reached a peak of number three on the New Zealand's singles chart. It has been certified platinum by the Recording Industry Association of New Zealand (RIANZ). The song also peaked the charts in Netherlands on the issue dated February 28, 2009.

In the United Kingdom, "Just Dance" debuted at number three on the issue dated January 4, 2009. It rose to number one on January 11, 2009, and remained at the top for three weeks. In January 12, 2009 interview, Gaga explained her feelings on topping the charts in the United Kingdom. She said, "It's been a long running dream to have a big hit in the UK - my fans there are so sexy and the people are so innovative and free in how they think about pop culture and music. I was in my apartment in Los Angeles getting ready to go to dance rehearsal when they called and told me, and I just cried." The track has achieved similar success throughout Europe reaching the top ten in countries like Austria, Denmark, Finland, Norway, Sweden, Switzerland and the top twenty of Belgium (Flanders and Wallonia) and France. Worldwide the song has sold 7.7 million digital copies.

The video was directed by music video director Melina Matsoukas, and is based on the thematic content of the song of being in a party. The video begins with Gaga arriving with her dancers, Dina and Pepper, at a house party which seems to have ended. One of the dancers puts a Discolite Boombox on, blaring the music through the house. The crowd at the party appear to be sleeping in different areas, and are awoken by the music. They all start to dance, and scenes of the party are inter cut with scenes of a scantily dressed Lady Gaga dancing in a poncho, with a disco ball or in a small rubber pool playing with an inflated killer whale. She wears a blue, lightning-bolt shaped sticker beneath her right eye like that on the single cover, which was a tribute to her music idol David Bowie. Colby O'Donis also appears in the video being flanked by several girls during the "When I come through on the dance floor" interlude. Cameo appearances are made by Akon, Space Cowboy and fellow label hip-hop band Flipsyde. MTV called the video as an ode to the "Me Decade". During an interview with Australian radio in September 2008, Gaga said that "The whole video is performance art about being drunk at a party." In an interview with About.com when asked regarding the shooting experience of the music video, Gaga explained further about the video and her experience behind shooting it. She said,

"Oh it was so fun, it was amazing. For me it was like being on a Martin Scorsese set. I've been so low budget for so long, and to have this incredibly amazing video was really very humbling. It was really fun, but you'll see if you ever come to a video shoot of mine one day – I'm very private about those things, I don't really talk to everybody. I'm not like the party girl running around. I might even seem to be a bit of a diva. I'm sort of with myself, in my work head space worrying about costumes, and if extras look right, and placement. I don't just show up for things, you know. That video was a vision of mine. It was Melina the director who wanted to do something, to have a performance art aspect that was so pop but it was still commercial, but that felt like lifestyle. It was all those things, I love it."

Lady Gaga performed the song on many television shows in the United States. She appeared on Jimmy Kimmel Live, The Tonight Show with Jay Leno, So You Think You Can Danceand The Ellen DeGeneres Show. In July, she performed the song during the swimsuit competition of the Miss Universe 2008 beauty pageant in Vietnam. In Australia she performed on Sunrise. Her performance caused controversy because of allegations that she was lip-synching. Gaga denied it and released a statement, saying:

"I was sick the day of the show but I absolutely, 100 per cent, was singing live. [...] have never lip-synched and never will. Even on my worst day, I never will."

She also performed it during her AOL sessions. "Just Dance" was added to the setlist of her first headlining The Fame Ball Tour where it was performed before the Encore. As the performance for the acoustic version of "Poker Face" ended, Gaga exited from the stage and a video interlude called "The Face" starts telling about Gaga's alternate persona Candy Warhol and teaching her to speak. As the video nears the end Gaga appears on the stage wearing a tutu shaped dress with pointed shoulderpads and peplum. Her dancers were clad in Louis Vuitton Steven Sprouse printed trousers which matched Gaga's shoes. The backdrop changes to show blinking disco lights and Gaga stands while wearing her video sunglasses which display the line "Pop Music Will Never Be Low Brow". A remix of the intro for "Just Dance" starts and Gaga starts singing it while moving around in choreographed dance moves as she is joined by her dancers on stage. During the "Half psychotic, synch-hypnotic" interlude, Gaga brings out her trademark disco stick again. The performance ends with Gaga and her dancers taking a bow in front of the stage and exiting with her DJ Space Cowboy. It was also added to the setlist of The Monster Ball Tour, performed as the second song of the list. After the opening song "Dance in the Dark", she strapped on a portable silver jewelled keyboard and started performing "Just Dance" while inside a white cube from which she emerged from the top, and the video screen came up. She was raised on a platform with a keytar over her shoulder as eight dancers in white bodysuits locked into steps below her.