The Kingdom of Prussia was a German kingdom that constituted the state of Prussia between 1701 and 1918. It was the driving force behind the unification of Germany in 1871 and was the leading state of the German Empire until its dissolution in 1918. Although it took its name from the region called Prussia, it was based in the Margraviate of Brandenburg. Its capital was Berlin.

The kings of Prussia were from the House of Hohenzollern. Brandenburg-Prussia, predecessor of the kingdom, became a military power under Frederick William, Elector of Brandenburg, known as "The Great Elector". As a kingdom, Prussia continued its rise to power, especially during the reign of Frederick II, more commonly known as Frederick the Great, who was the third son of Frederick William I. Frederick the Great was instrumental in starting the Seven Years' War (1756–63), holding his own against Austria, Russia, France and Sweden and establishing Prussia's role in the German states, as well as establishing the country as a European great power. After the might of Prussia was revealed, it was considered as a major power among the German states. Throughout the next hundred years Prussia went on to win many battles, and many wars. Because of its power, Prussia continuously tried to unify all the German states (excluding the German cantons in Switzerland) under its rule, and whether Austria would be included in such a unified German domain was an ongoing question.