Daniel Webster Hoan (March 12, 1881 – June 11, 1961) was an American politician who served as the 32nd Mayor of Milwaukee, Wisconsin from 1916 to 1940. A lawyer who had served as Milwaukee City Attorney from 1910 to 1916, Hoan was a prominent figure in Socialist politics and Milwaukee's second Socialist mayor. His 24-year administration remains the longest continuous Socialist administration in United States history.