Fantasy was released on September 12, 1995 by  Columbia Records as the lead single for her fifth studio album, Daydream (1995). The song was written by Carey and Dave Hall, both serving as primary producers alongside Sean Combs. The song heavily samples Tom Tom Club‘s 1981 song “Genius of Love,” and incorporates various other beats and grooves arranged by the former.

Carey described how the idea to sample the song became a reality:

I was listening to the radio and heard ‘Genius of Love’, and I hadn’t heard it in a long time. It reminded me of growing up and listening to the radio and that feeling the song gave me seemed to go with the melody and basic idea I had for “Fantasy.” I initially told Dave about the idea, and we did it. We called up the Tom Tom Club and they were really into it.