The 5th U-boat Flotilla (German 5. Unterseebootsflottille), also known as Emsmann Flotilla, was a U-boat flotilla of the German Kriegsmarine during World War II. The flotilla was formed in December 1938 in Kiel under the command of Korvettenkapitän Hans-Rudolf Rösing. It was named in honour of Oberleutnant Hans Joachim Emsmann, a U-boat commander during World War I, who died on 28 October 1918 after his U-boat was sunk by a mine. The flotilla was disbanded in January 1940 and the boats were all transferred to 1st Flotilla.