"Last Friday Night (T.G.I.F.)" is a song by American recording artist Katy Perry. The song was produced by Lukasz Gottwald and Max Martin, who also co-wrote the song with Perry and Bonnie McKee at Playback Recording Studio for Perry's third studio album, Teenage Dream. Perry stated that she was inspired to write the track after a night of wild partying and streaking. It was released as the album's fifth single on June 6, 2011 through Capitol Records with a remix featuring American hip-hop recording artist Missy Elliott released to U.S. radio stations and digital retailers on August 8, 2011, this version was included in Teenage Dream: The Complete Confection edition. Musically, the song is prominent dance-pop with influences of pop-rock, and the lyrics are about drunken fun and debauchery. Some of the risque lyrics in the song are often censored in radio versions of the song.

The song received mixed to positive reviews from music critics, with some of them highlighting its playful and catchy nature. However, critics were divided regarding the song's lyrical content; some referred it to as funny and sexy, while others dismissed it as lifeless. The song enjoyed chart success in North America, reaching number one on the U.S. Billboard Hot 100 and Canadian Hot 100. It also topped U.S. charts like Hot Digital Songs, Pop Songs, Radio Songs, and Hot Dance Club charts, like all of her previous singles. It also reached number one in Slovakia and the Czech Republic and has attained top-ten positions in Austria, Ireland, Italy and Poland.

Katheryn Elizabeth Hudson (born October 25, 1984), known by her stage name Katy Perry, is an American singer, songwriter and actress. Perry grew up with gospel music, and during her first year of high school she pursued a music career as Katy Hudson, releasing her first studio album called Katy Hudson which failed to chart. She recorded a solo album later, which was never released. After signing with Capitol Music Group in 2007, her fourth record label in seven years, she adopted the stage name Katy Perry.

She first gained recognition with the release of her first mainstream album, One of the Boys in 2008, which spawned three Billboard Hot 100 top-ten songs—"I Kissed A Girl", "Hot n Cold" and "Waking Up In Vegas". Perry supported the album with her Hello Katy Tour. In 2010, her third studio album, Teenage Dream (2010), which topped the Billboard 200 chart, and spawned five number one singles—"California Gurls", "Teenage Dream", "Firework", "E.T." and "Last Friday Night (T.G.I.F.)"—Teenage Dream was the only album (after Michael Jackson's Bad)—to do so, and the first female in history to achieve this milestone. She embarked on the California Dreams Tour, which grossed nearly $60 million worldwide. Perry re-released the album under the name of Teenage Dream: The Complete Confection on March 26, 2012, and the re-release has already spawned the number-one single "Part of Me".

Melissa Arnette "Missy" Elliott (born July 1, 1971) is an American rapper, singer-songwriter, record producer, dancer and actress. A five-time Grammy Award winner, Elliott, with record sales of over seven million in the United States, is the only female rapper to have six albums certified platinum by the RIAA, including one double platinum for her 2002 album Under Construction. Elliott is known for a series of hits and diverse music videos, including "The Rain (Supa Dupa Fly)", "Hot Boyz", "Get Ur Freak On", "One Minute Man", "4 My People", "Work It", "Pass That Dutch", and "Lose Control". In addition, she has worked extensively as a songwriter and producer for other artists, both alone and with her fellow producer and childhood friend Timbaland, with whom she received her first production credit on R&B singer Ginuwine's 1996's album Ginuwine...the Bachelor.