German submarine U-331 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II, famous for sinking the battleship HMS Barham.

The submarine was laid down on 26 January 1940 at the Nordseewerke yard at Emden, launched on 20 December 1940, and commissioned on 31 March 1941 under the command of Oberleutnant zur See Hans-Diedrich Freiherr von Tiesenhausen.

She was tracked by the RAF and crippled before being destroyed by the Royal Navy Fleet Air Arm on 17 November 1942 with the loss of most of her crew.

The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two AEG GU 460/8–27 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged.

On 17 November she landed seven men of the Lehrregiment Brandenburg[6] east of Ras Gibeisa, on a mission to blow up a railway line near the coast, which failed.

[7] On 25 November 1941, north of Sidi Barrani, U-331 fired three torpedoes into the British Queen Elizabeth-class battleship HMS Barham.

500 Squadron RAF, with the forward hatch jammed open, preventing the submarine from diving, and she signalled surrender to the Hudson.

[15] The destroyer HMS Wilton was ordered to seize the submarine, but an airstrike by three Fairey Albacore torpedo-bombers from 820 Naval Air Squadron escorted by two Grumman Martlet fighters of 893 Naval Air Squadron was launched from the British aircraft carrier HMS Formidable against the damaged submarine.