The Royal Prussian Army (Königlich Preußische Armee) was the army of the Kingdom of Prussia. It was vital to the development of Brandenburg-Prussia as a European power.

The Prussian Army had its roots in the meager mercenary forces of Brandenburg during the Thirty Years War. Elector Frederick William developed it into a viable standing army, while King Frederick William I of Prussia drastically increased its size. King Frederick the Great led the disciplined Prussian troops to victory during the 18th century Silesian Wars and increased the prestige of the Kingdom of Prussia.

The army was outdated by the beginning of the Napoleonic Wars, and Prussia was defeated by France in the War of the Fourth Coaltion. However, under the leadership of Gerhard von Scharnhorst, Prussian reformers began modernizing the Prussian Army, which contributed greatly to the defeat of Napoleon Bonaparte during the War of the sixth Coalition. Conservatives halted some of the reforms, however, and the army subsequently became a bulwark of the conservative Prussian government.

The Prussian Army was successful in 19th century wars against Denmark, Austria and France, allowing Prussia to unify Germany and create the German Empire in 1871. The Prussian Army formed the core of the Imperial German Army, which was replaced after World War I with the Reichswehr.

Aantal Pruizen; 18.