The 1957 United States Senate special election in Wisconsin took place on August 27, 1957, to elect a U.S. Senator to complete the unexpired term of Senator Joseph McCarthy, who died on May 2, 1957.
Unlike most states Wisconsin law did not allow for the gubernatorial appointment of an interim Senator.
Democratic nominee William Proxmire defeated Republican nominee and former Governor Walter J. Kohler Jr.
Primary elections were held on July 30, 1957.
The three minor candidates all technically ran as independents.