The 28 cm SK L/40 was a German naval gun that was used in World War I and World War II as the main armament of the Braunschweig- and Deutschland-class pre-dreadnoughts.

The Braunschweig-class battleships were a group of five pre-dreadnought battleships of the German Kaiserliche Marine built in the early 1900s. They were the first class of battleships authorized under the Second Naval Law, a major naval expansion program. The class comprised five ships—Braunschweig, Elsass, Hessen, Preussen, and Lothringen—and they were an improvement over the preceding Wittelsbach class. The Braunschweigs mounted a more powerful armament of 28 cm (11 in) and 17 cm (6.7 in) guns. Less than two years after the first members of the class entered service, the ships were rendered obsolescent by the British all-big-gun battleship Dreadnought, which curtailed their careers.