| Washington King | |
| Order: | 15th Mayor of St. Louis, Missouri |
| Term Start: | 1855 |
| Term End: | 1856 |
| Predecessor: | John How |
| Successor: | John How |
| Birth Date: | October 5, 1815 |
| Birth Place: | New York City, US |
| Death Place: | St. Louis, Missouri, US |
| Party: | Know Nothing |
Washington King (October 5, 1815 – August 27, 1861) was the 15th mayor of St. Louis, Missouri, serving from 1855 to 1856.
Mayor King was a passenger on the Pacific Railroad excursion train that crashed through the temporary bridge over the Gasconade River on November 1, 1855. He was badly cut in the accident.[1] Subsequently, he declared a day of mourning for the victims.