German submarine U-161 was a Type IXC U-boat of Nazi Germany's Kriegsmarine built for service during World War II. The keel for this boat was laid down on 23 March 1940 at the Deutsche Schiff und maschinenbau AG, Bremen yard as yard number 700. She was launched on 1 March 1941 and commissioned on 8 July under the command of Kapitänleutnant Hans-Ludwig Witt.

The Type IX U-boat was designed by Nazi Germany's Kriegsmarine in 1935 and 1936 as a large ocean-going submarine for sustained operations far from the home support facilities. Type IX boats were briefly used for patrols off the eastern United States in an attempt to disrupt the stream of troops and supplies bound for Europe. It was derived from the Type IA, and appeared in various sub-types.