German submarine U-1020 was a Type VIIC/41 U-boat of Nazi Germany's Kriegsmarine during World War II.

She was ordered on 13 June 1942, and was laid down on 30 April 1943, at Blohm & Voss, Hamburg, as yard number 220.

She was launched on 22 March 1944, and commissioned under the command of Oberleutnant zur See Otto Eberlein on 17 May 1944.

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 BBC GG UB 720/8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged.

Forty-nine days into her patrol, 9 January 1945, U-1020 struck a British mine east of Dundee in the North Sea.