SMS Scharnhorst was an armored cruiser of the Imperial German Navy, built at the Blohm & Voss shipyard in Hamburg, Germany. She was the lead ship of her class, which included SMS Gneisenau. Scharnhorst and her sister were enlarged versions of the preceding Roon class; they were equipped with a greater number of main guns and were capable of a higher top speed. The ship was named after the Prussian military reformer General Gerhard von Scharnhorst and commissioned into service on 24 October 1907.

The armored cruiser was a type of warship of the late 19th and early 20th centuries. It was designed like other types of cruisers to operate as a long-range, independent warship, capable of defeating any ship apart from a battleship and fast enough to outrun any battleship it encountered.