U-57 may refer to one of the following German submarines:
- SM U-57, the lead ship of the Type U 57 class of submarines; launched in 1915 and that served in the First World War until surrendered on 24 November 1918; broken up at Cherbourg in 1921
- During the First World War, Germany also had these submarines with similar names:
- SM UB-57, a Type UB III submarine launched in 1917 and sunk on 14 August 1918
- SM UC-57, a Type UC II submarine launched in 1916 and disappeared after 18 November 1917
- During the First World War, Germany also had these submarines with similar names:
- German submarine U-57 (1938), a Type IIC submarine that served in the Second World War until sunk 3 September 1940; raised later in the month and returned to service on 11 January 1941; scuttled on 3 May 1945
This article includes a list of ships with the same or similar names. If an internal link for a specific ship led you here, you may wish to change the link to point directly to the intended ship article, if one exists.