| Election Name: | 1991 San Francisco mayoral election |
| Country: | San Francisco |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1987 San Francisco mayoral election |
| Previous Year: | 1987 |
| Next Election: | 1995 San Francisco mayoral election |
| Next Year: | 1995 |
| Election Date: | November 5, 1991 December 10, 1991 |
| Image1: | File:Frank JORDAN, October 1999 (1).jpg |
| Candidate1: | Frank Jordan |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 98,491 |
| Percentage1: | 52.01% |
| Candidate2: | Art Agnos |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 90,875 |
| Percentage2: | 47.99% |
| Mayor | |
| Before Election: | Art Agnos |
| Before Party: | Democratic Party (United States) |
| After Election: | Frank Jordan |
| After Party: | Democratic Party (United States) |
The 1991 San Francisco mayoral election was held on November 5, 1991, with a runoff election on December 10 that year. Incumbent mayor Art Agnos, after having won nearly 70% of the vote in 1987, scraped by with less than a third of the vote in the first round and was narrowly unseated by Chief of Police Frank Jordan in the runoff.
Agnos' strong support of demolishing the Embarcadero Freeway after the 1989 Loma Prieta earthquake caused San Francisco's Chinatown voters to turn against him, contributing to his narrow loss.
| Frank Jordan | 59,928 | 31.88% | |
| Art Agnos (incumbent) | 51,714 | 27.51% | |
| Angela Alioto | 34,910 | 18.57% | |
| Tom Hsieh | 18,241 | 9.70% | |
| Richard Hongisto | 17,663 | 9.40% | |
| Gloria La Riva | 2,552 | 1.36% | |
| Joni Jacobs | 1,397 | 0.74% | |
| Cesar Ascarrunz | 724 | 0.39% | |
| Ellis Keyes | 337 | 0.18% | |
| Dehnert C. Queen | 310 | 0.17% | |
| Peter Planteen | 214 | 0.11% | |
| Total votes: | 187,990 | ||
| Voter turnout: | 47.61% | ||
| Frank Jordan | 98,491 | 52.01% | |
| Art Agnos (incumbent) | 90,875 | 47.99% | |
| Total votes: | 189,366 | ||
| Voter turnout: | 50.73% | ||