SMS Westfalen was one of the Nassau-class battleships, the first four dreadnoughts built for the German Imperial Navy. Westfalen was laid down at AG Weser in Bremen on 12 August 1907, launched nearly a year later on 1 July 1908, and commissioned into the High Seas Fleet on 16 November 1909. The ship was equipped with a main battery of twelve 28 cm (11 in) guns in six twin turrets in an unusual hexagonal arrangement.

The Nassau class was a group of four dreadnought battleships built for the German Kaiserliche Marine in the early 1900s. The class comprised Nassau, the lead ship, Rheinland, Posen, and Westfalen. All four ships were laid down in mid-1907, and completed by late 1910. Though commonly perceived as having been built in response to the British Dreadnought, their design traces its origin to 1903; they were in fact a response to Dreadnought's predecessors of the Lord Nelson class. The Nassaus adopted a main battery of twelve 28 cm (11 in) guns in six twin-gun turrets in an unusual hexagonal arrangement. Unlike many other dreadnoughts, the Nassau-class ships retained triple-expansion steam engines instead of more powerful steam turbines.