This is a list of the U.S. Billboard magazine Hot 100 number-ones of 1991. The longest running number-one single of 1991 is "(Everything I Do) I Do It for You" by Bryan Adams, which attained seven weeks at number-one. ("Black or White" by Michael Jackson would also spend a total of seven weeks at #1, but only four of those weeks were in the 1991 calendar year.)
That year, 14 acts earn their first number one song, such as Surface, C+C Music Factory, Freedom Williams, Timmy T, Londonbeat, Hi-Five, Extreme, EMF, Color Me Badd, Marky Mark and the Funky Bunch, Loleatta Holloway, Karyn White, The New Power Generation, and P.M. Dawn. Mariah Carey and Paula Abdul were the only acts to hit number one more than once, with Mariah Carey having the most with three and Paula Abdul having two.
The November 30 chart ("Set Adrift on Memory Bliss") was the first Hot 100 to be compiled with Soundscan data.
An asterisk (*) by a date indicates an unpublished, "frozen" week, due to the special double issues that Billboard published in print at the end of the year for their year-end charts. This was the final year that there was no Hot 100 during this unpublished week. While the double issues continued beyond 1991, the charts themselves would still be compiled, available through their electronic and online services.