| Election Name: | 1903 San Diego mayoral election |
| Flag Image: | Flag of San Diego, California.svg |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1901 San Diego mayoral election |
| Previous Year: | 1901 |
| Next Election: | 1905 San Diego mayoral election |
| Next Year: | 1905 |
| Nominee1: | Frank P. Frary |
| Party1: | Republican Party (US) |
| Popular Vote1: | 1,469 |
| Percentage1: | 49.0% |
| Nominee2: | James E. Wadham |
| Party2: | Democratic Party (US) |
| Popular Vote2: | 1,312 |
| Percentage2: | 43.7% |
| Mayor | |
| Before Election: | Frank P. Frary |
| Before Party: | Republican Party (US) |
| After Election: | Frank P. Frary |
| After Party: | Republican Party (US) |
The 1903 San Diego mayoral election was held on April 7, 1903, to elect the mayor for San Diego. Incumbent Mayor Frank P. Frary was reelected to a second term with a plurality of the votes.
Incumbent Mayor Frank P. Frary, a Republican, stood for reelection to a second two-year term. His reelection was contested by James E. Wadham, a Democrat, and Frank Simpson, a Socialist. Wadham ran on a Democratic Party platform that advocated for public ownership of gas and electricity as well as the development of pueblo lands.
On April 7, 1903, Frary was reelected mayor with a plurality of 49.0 percent of the vote. Wadham came in second with 43.7 percent of the vote. This represented an 8.4 percent swing in the Democrat's favor compared to 1901, but was not enough to defeat Frary. Simpson came in third with 7.3 percent.