U-17 may refer to one of the following German submarines:
- SM U-17 (Germany), was the lead ship of the Type U 17 class of submarines; launched in 1912 and served in the First World War until stricken on 27 January 1919
- During the First World War, Germany also had these submarines with similar names:
- SM UB-17, a Type UB I submarine launched in 1915 that disappeared in March 1918
- SM UC-17, a Type UC II submarine launched in 1916 and surrendered 26 November 1918
- During the First World War, Germany also had these submarines with similar names:
- German submarine U-17 (1935), a Type IIB submarine that served in the Second World War and was scuttled on 5 May 1945
- German submarine U-17 (S196), a Type 206 submarine of the Bundesmarine that was launched in 1973 and decommissioned in 2010
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.