German submarine U-173 was a Type IXC U-boat of the Nazi German Kriegsmarine during World War II. She was laid down at the AG Weser yard in Bremen as werk 1013, launched on 11 August 1941 and commissioned on 15 November with Fregattenkapitän Heinz-Ehler Beuke in command. U-173 began her service career with training as part of the 4th U-boat Flotilla. She was re-assigned to the 2nd flotilla for operations on 1 July 1942.