German submarine U-155 was a Type IXC U-boat of the Nazi German Kriegsmarine built for service during World War II. Her keel was laid down on October 1, 1940 by AG Weser in Bremen as 'werk' 997. She was launched on May 12, 1941 and commissioned on August 23, with Kapitänleutnant Adolf Cornelius Piening in command. Piening was relieved in February 1944 (after being promoted to Korvettenkapitän), by Oberleutnant zur See Johannes Rudolph.