The IV Army Corps / IV AK () was a corps level command of the Prussian and then the Imperial German Armies from the 19th Century to World War I. It was established on 3 October 1815 as the General Command in the Duchy of Saxony (Generalkommando im Herzogtum Sachsen) and became the IV Army Corps on August 30, 1818. Its headquarters was in Magdeburg and its catchment area included the Prussian Province of Saxony and the adjacent Saxon Duchies (Saxe-Altenburg, Anhalt) and Principalities (Schwarzburg-Sondershausen, Schwarzburg-Rudolstadt, Reuss Elder Line and Reuss Junior Line).