SM U-32 was a German Type U 31 U-boat of the Imperial German Navy.
Her construction was ordered on 29 March 1912 and her keel was laid down on 8 November 1912 by Germaniawerft of Kiel. She was launched on 28 January 1914 and commissioned on 3 September 1914 under the command of Edgar von Spiegel von und zu Peckelsheim. On 1 February 1916 Spiegel was relieved by Kurt Hartwig who commanded the boat until 16 February 1918 when Karl Albrecht took over. Albrecht commanded her until her loss.
U-32 conducted 11 patrols, sinking 37 merchant ships totalling and one warship for 14,000 tons. On 9 January 1917, to the East of Malta, U-32 sank the British pre-dreadnought battleship , with the loss of 15 lives.
Type U 31 submarines were double-hulled ocean-going submarines similar to Type 23 and Type 27 subs in dimensions and differed only slightly in propulsion and speed. They were considered very good high sea boats with average manoeuvrability and good surface steering.
U-32 had an overall length of , her pressure hull was long. The boat's beam was (o/a), while the pressure hull measured . Type 31s had a draught of with a total height of . The boats displaced a total of ; when surfaced and when submerged.
U-32 was fitted with two Germania 6-cylinder two-stroke diesel engines with a total of for use on the surface and two Siemens-Schuckert double-acting electric motors with a total of for underwater use. These engines powered two shafts each with a propeller, which gave the boat a top surface speed of , and when submerged. Cruising range was at on the surface, and at under water. Diving depth was .
The U-boat was armed with four torpedo tubes, two fitted in the bow and two in the stern, and carried 6 torpedoes. Additionally U-32 was equipped in 1915 with two Uk L/30 deck guns. The boat's complement was 4 officers and 31 enlisted.
On 8 May 1918 north-west of Malta she was shelled and then depth charged by and sunk with all hands, 41 dead.