The 1913 San Diego mayoral election was held on April 8, 1913 to elect the mayor for San Diego. Charles F. O'Neall and George Marston received the most votes in the primary election and advanced to the runoff. O'Neall was then elected mayor with a majority of the votes.
In the campaign, Marston emphasized projects that would lead to a beautiful and prosperous city, including harbor improvements, a new dry dock, a navy center and a railroad to Arizona. O'Neall emphasized the importance of developing commerce and industry over public parks and recreation.
On March 25, 1913, O'Neall and Marston received the two highest vote totals in the primary and advanced to the general election. O'Neall was then elected mayor on April 8, 1913 with a majority of the votes in the runoff.