German submarine U-668 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 11 October 1941 at the Howaldtswerke yard at Hamburg, launched on 5 October 1942, and commissioned on 16 November 1942 under the command of Oberleutnant zur See Wolfgang von Eickstedt. Attached to 5th U-boat Flotilla based at Kiel, U-668 completed her training period on 31 March 1944 and was assigned to front-line service.