The H class was a series of battleship designs for Nazi Germany's Kriegsmarine, which were intended to fulfill the requirements of Plan Z in the late 1930s and early 1940s. The first variation, "H-39," called for six ships to be built, essentially as enlarged Bismarck-class battleships with 40.6 cm (16.0 in) guns and diesel propulsion. The "H-41" design improved the "H-39" ship with still larger main guns, eight 42 cm (16.5 in) weapons, and reinforced deck armor. The Construction Office of the Oberkommando der Marine (OKM) concluded their work the "H-41" design, and were not involved subsequent plans. Two of them, "H-42" and "H-43", increased the main battery yet again, with 48 cm (18.9 in) pieces, and the enormous "H-44" design ultimately resulted with 50.8 cm (20.0 in) guns. The ships ranged in size from the "H-39", which was 277.8 m (911 ft 5 in) long on a displacement of 56,444 t (55,553 long tons), to the "H-44", at 345 m (1,131 ft 11 in) on a displacement of 131,000 t (129,000 long tons). Most of the designs had a proposed top speed in excess of 30 knots (56 km/h).

Due to the outbreak of World War II in September 1939, none of the ships was ever completed; only the first two of the "H-39" ships were laid down. What work that had been accomplished was halted; the assembled steel remained on the slipway until November 1941, when the OKM ordered it be sent for scrap and used for other purposes. Contracts for the other four "H-39" type ships had been awarded, but no work was begun on any of them before they were canceled. None of the subsequent designs progressed further than planning stages.