German submarine U-126 was a Type IXC U-boat of Nazi Germany's Kriegsmarine during World War II. In six patrols, she sank 25 ships for a total of 112,489 gross register tons (GRT). She was laid down at the DeSchiMAG AG Weser yard in Bremen as yard number 989 on 1 June 1940, launched on 31 December and commissioned on 22 March 1941 under Kapitänleutnant Ernst Bauer.