John George of Brandenburg (German: Johann Georg) (11 September 1525 – 8 January 1598) was a Prince-elector of the Margraviate of Brandenburg (1571–1598) and a Duke of Prussia. A member of the House of Hohenzollern, he was the son of Joachim II Hector, Elector of Brandenburg, and his first wife Magdalena of Saxony.
Faced with large debts accumulated during the reign of his father, John George instituted a grain tax which drove part of the peasantry into dependence on a nobility that was exempt from taxation. Though a staunch Lutheran opposed to the rise of Calvinism, he permitted the admission of Calvinist refugees from the wars in the Spanish Netherlands and France. He was succeeded by his son Joachim Frederick.
Upon the death of his kinsman Albert I, Duke of Prussia in 1568, the Duchy of Prussia was inherited by the latter's underage son Albert Frederick. John George's father was a co-inheritor of the Duchy of Prussia. In 1577 the Brandenburg electors became co-regent with Duke Albert Frederick of Prussia.
John George was married three times.
His first wife was Princess Sophie of Legnica (ca. 1525 – 6 February 1546), whom he married in 1545. They had one child together:
Secondly, he married Margravine Sabina of Brandenburg-Ansbach (12 May 1529 – 2 November 1575), daughter of George, Margrave of Brandenburg-Ansbach, in 1548. They had the following children: