German submarine U-27 was a Type VIIA U-boat of Nazi Germany's Kriegsmarine built for service in World War II. Her keel was laid down in November 1935 in Bremen. She was commissioned in August 1936 with Korvettenkapitän Hans Ibbeken in command. Ibbeken was relieved on 4 October 1937, by Johannes Franz, who commanded the boat until 6 June 1939 when Hans-Georg von Friedeburg assumed command for barely one month. He was relieved on 8 July again by Johannes Franz, who commanded the boat until her loss on 20 September 1939.

Hans-Georg von Friedeburg was a German admiral, the deputy commander of the U-boat Forces of Nazi Germany and the second-to-last Commander-in-Chief of the Kriegsmarine. He was the only representative of the armed forces to be present at the signing of the German instruments of surrender in Luneburg Heath on 4 May 1945, in Reims on 7 May and in Berlin on 8 May 1945. Von Friedeburg committed suicide shortly afterwards, upon the dissolution of the Flensburg Government.