German submarine U-142 was a Type IID U-boat of Nazi Germany's Kriegsmarine during World War II. Her keel was laid down on 12 December 1939 by Deutsche Werke in Kiel as yard number 271. She was launched on 27 July 1940 and commissioned on 4 September 1940 with Leutnant zur See Asmus Nicolai Clausen in command. U-142 began her service life with the 1st U-boat Flotilla. She was then assigned to the 24th Flotilla and subsequently to the 22nd Flotilla where she conducted three patrols, but did not sink or damage any ships. She spent the rest of the war as a training vessel.