Stephen Palfrey Webb (March 20, 1804 - September 29, 1879) was third and twelfth Mayor of Salem, Massachusetts, serving 1842-1845 and 1860-1863, and the sixth Mayor of San Francisco, California from 1854-1855. Webb served in the Massachusetts House of Representatives and the Massachusetts Senate. He was elected mayor of Salem, Massachusetts in 1842, 1843, and 1844. Webb was also Treasurer and Clerk of the Essex Railroad in 1849. Webb moved to San Francisco in approximately 1853 and was elected mayor for a single term with backing from the Know Nothing movement in 1854. He prepared a report about the vigilance committees in 1874 entitled A Sketch of the Causes, Operations and Results of the San Francisco Vigilance Committee in 1856.