"Fantasy" is a song co-written and co-produced by American singer Mariah Carey and Dave Hall, and recorded for Carey's fifth album Daydream(1995). It is built around a sample of the Tom Tom Club's single "Genius of Love" (1981), which was written by Tina Weymouth, Chris Frantz, Steven Stanley and Adrian Belew. It was released as the album's first single in 1995. The urban remix of "Fantasy" features Ol' Dirty Bastard. For the sixth year in a row, Mariah Carey received a Grammy Award nomination for Best Female Pop Vocal Performance. The cover of the single was shot by top fashion photographer Steven Meisel. The cover for her album Daydreamis a cropped version of the single cover. The song was number 1 for eight consecutive weeks and is one of Carey's signature songs.

"Fantasy" became Carey's ninth number 1 single on the U.S. Billboard Hot 100 chart. It was the first single by a female artist to debut at number 1 in the U.S., and only the second single to do so after "You Are Not Alone" by Michael Jackson. It spent eight weeks at the top of the chart, from September 24 to November 18, 1995, Carey's longest stay at the time alongside "Dreamlover" (1993). It replaced " Gangsta's Paradise" by Coolio, and was replaced by Whitney Houston's "Exhale (Shoop Shoop)". "Fantasy" spent twenty-three weeks in the top forty and was successful on other Billboardformats, including the R&B and dance charts. Its strong sales led it to be certified double platinum by the RIAA, Carey's first single to do so. It was ranked number 7 on the Hot 100 year-end charts for 1995 and 49 on the 1996 year-end charts. The song was as well featured in the 1998 Rush Hour movie.

The single topped the charts in Canada, Australia and New Zealand and reached the top five in the United Kingdom. It remained at the top of the Canadian Singles Chart for twelve weeks, a record it shared with six other singles until the release of "I'll Be Missing You" (1997) by Puff Daddy featuring Faith Evans. "Fantasy" also reached the top ten in most countries across Europe, and the top twenty on the Oricon chart in Japan.

The single's music video was the first that Carey directed entirely on her own. She can be seen exploring an amusement park (Playland, located in Rye, New York), on roller blades and riding on a roller coaster, before joining a group of hip hop dancers after nightfall. The video also contains a scene involving an lovable young girl who tries to emulate Carey and whose character reappears in the video for Carey's single "Shake It Off" (2005). The video shoot took place in mid-August 1995.

Carey worked with producer Puff Daddy to create the official remix, the Bad Boy remix of "Fantasy". The Bad Boy remix used guest raps from Ol' Dirty Bastard and background vocals by Puff Daddy. Some of the song's R&B elements were removed for the remix, while the bassline and "Genius of Love" sample were emphasized. There is a version omitting Ol' Dirty Bastard's verses.

Carey re-recorded vocals for club remixes of the song by David Morales. One of these remixes won the Winter Music Conference National Dance Award for Dance Record of the Year.

Worldwide CD single

UK #1/U.S. CD maxi-single

UK CD maxi-single #2