German submarine U-1166 was a Type VIIC/41 U-boat of Nazi Germany's Kriegsmarine during World War II.

She was launched on 28 August 1943, and commissioned under the command of Oberleutnant zur See Herbert Wagner on 8 December 1943.

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 SSW GU 343/38-8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged.

When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph).

On 3 May 1945, U-1166 was scuttled at the Deutsche Werke shipyard in Kiel off of dry dock No.