German submarine U-24 was a Type IIB U-boat that was in service of Nazi Germany's Kriegsmarine during World War II.

She was laid down on 21 April 1936 at the F. Krupp Germaniawerft in Kiel with yard number 554, launched on 24 September and commissioned into the Kriegsmarine on 10 October.

The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of 700 metric horsepower (510 kW; 690 shp) for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of 460 metric horsepower (340 kW; 450 shp) for use while submerged.

[1] To serve in the 30th U-boat Flotilla, she was transported in sections along the Danube to the Romanian port of Galați.

[2] On 25 August 1944, U-24 was scuttled at Constanţa, on the Romanian Black Sea coast to prevent the advancing Soviet forces from capturing it.