The Helgoland class was the second class of dreadnought battleships to be built for the German Kaiserliche Marine. Constructed from 1908 to 1912, the class comprised four ships: Helgoland, the lead ship; Oldenburg; Ostfriesland; and Thüringen. The design was a significant improvement over the previous Nassau-class ships; they had a larger main battery—30.5 cm (12 in) main guns instead of the 28 cm (11 in) weapons mounted on the earlier vessels—and an improved propulsion system. The Helgolands were easily distinguished from the preceding Nassaus by the three funnels that were closely arranged, compared to the two larger funnels of the previous class. The ships retained the hexagonal main battery layout of the Nassau class.

The dreadnought was the predominant type of battleship in the early 20th century. The first of the kind, the Royal Navy's HMS Dreadnought, had such an effect when launched in 1906 that similar battleships built after her were referred to as "dreadnoughts", and earlier battleships became known as pre-dreadnoughts. Her design had two revolutionary features: an "all-big-gun" armament scheme, with an unprecedented number of heavy-calibre guns, and steam turbine propulsion. As dreadnoughts became a crucial symbol of national power, the arrival of these new warships renewed the naval arms race between the United Kingdom and Germany. Dreadnought races sprang up around the world, including in South America, lasting up to the beginning of World War I. Successive designs increased rapidly in size and made use of improvements in armament, armour, and propulsion throughout the dreadnought era. Within five years, new battleships outclassed Dreadnought herself. These more powerful vessels were known as "super-dreadnoughts". Most of the original dreadnoughts were scrapped after the end of World War I under the terms of the Washington Naval Treaty, but many of the newer super-dreadnoughts continued serving throughout World War II.