| Election Name: | 1891 San Diego mayoral election |
| Flag Image: | Flag of San Diego, California.svg |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1889 San Diego mayoral election |
| Previous Year: | 1889 |
| Next Election: | 1893 San Diego mayoral election |
| Next Year: | 1893 |
| Image1: | Matthew Sherman.jpg |
| Image1 Size: | x150px |
| Nominee1: | Matthew Sherman |
| Party1: | Republican Party (US) |
| Popular Vote1: | 1,282 |
| Percentage1: | 50.6% |
| Nominee2: | J.W. Hughes |
| Party2: | Democratic Party (US) |
| Popular Vote2: | 1,251 |
| Percentage2: | 49.4% |
| Mayor | |
| Before Election: | Douglas Gunn |
| Before Party: | Republican Party (US) |
| After Election: | Matthew Sherman |
| After Party: | Republican Party (US) |
The 1891 San Diego mayoral election was held on April 7, 1891, to elect the mayor for San Diego. Matthew Sherman was elected Mayor with a majority of the votes.
Unlike the 1889 election, which was contested solely between Republicans on different tickets, the 1891 featured candidates from both the Republicans and the Democrats. Matthew Sherman was the candidate on the Republican side running against J.W. Hughes on the Democratic side.
On April 7, 1891, Sherman was elected mayor with 50.6 percent of the vote to Hughes's 49.4 percent.