U-159 may refer to one of the following German submarines:
- SM U-159, a Type U 158 submarine launched in 1918 during World War I but unfinished at the end of the war; broken up
- German submarine U-159 (1941), a Type IXC submarine that served in the Second World War until sunk on 28 July 1943
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.