Gneisenau was a German capital ship, alternatively described as a battleship and battlecruiser, of the German Kriegsmarine. She was the second vessel of her class, which included one other ship, Scharnhorst. The ship was built at the Deutsche Werke dockyard in Kiel; she was laid down on 6 May 1935 and launched on 8 December 1936. Completed in May 1938, the ship was armed with a main battery of nine 28 cm C/34 guns in three triple turrets, though there were plans to replace these weapons with six 38 cm (15 in) SK C/34 guns in twin turrets.
Gneisenau and Scharnhorst operated together for much of the early portion of World War II, including sorties into the Atlantic to raid British merchant shipping. During her first operation, the two ships engaged the auxiliary cruiser HMS Rawalpindi in a short battle. Gneisenau and Scharnhorst participated in Operation Weserübung, the German invasion of Norway. During operations off Norway, the two ships engaged the battlecruiser HMS Renown and sank the aircraft carrier HMS Glorious. Gneisenau was damaged in the action with Renown and later torpedoed by a British submarine off Norway. After a successful raid in the Atlantic in 1941, Gneisenau and her sister put in at Brest, France. The two battleships were the subject of repeated bombing raids by the RAF; Gneisenau was hit several times during the raids, though she was ultimately repaired.
In early 1942, the two ships made a daylight dash up the English Channel from occupied France to Germany. After reaching Kiel in early February, the ship went into drydock. On the night of 26 February, the British launched an air attack on the ship; one bomb penetrated her armored deck and exploded in the forward ammunition magazine, causing serious damage and a large number of casualties. The repairs necessitated by the damage were so time consuming that it was determined to rebuild the ship to accommodate the 38 cm guns as originally intended. The 28 cm guns were removed and used as shore batteries. The aft turret (Caesar) was installed at Austrått fort in Ørland, Norway where it still remains as a museum exhibit. The mid-ship turret (Bruno) was used at Fjell festning near Bergen. The front turret (Anton) was heavily damaged, thus individual guns were moved to separate forts in Denmark and the Netherlands. In 1943, Hitler ordered the cessation of conversion work, and on 27 March 1945, she was sunk as a blockship in Gdynia (Gotenhafen) in German-occupied Poland. She was eventually broken up for scrap in 1951.