(19 November 1413 – 10 February 1471), nicknamed "the Iron" (der Eiserne) and sometimes "Irontooth" (Eisenzahn), was a Prince-elector of the Margraviate of Brandenburg from 1440 until his abdication in 1470, and was a member of the House of Hohenzollern.

Unlike his father, he turned away from imperial politics and concentrated on his efforts to pacify the nobility and towns of the electorate.

In 1448 the Berliner Unwille (indignation) against the cession of the city's territory for an electoral stronghold culminated in open revolt, when the citizens flooded the excavation of the future Stadtschloss.

In 1453, Frederick II, in his position as the Margrave of Brandenburg, was sent a letter from Rhodes, penned by the Grand Master of the Knights of St John, notifying him of the Fall of Constantinople and requesting he send them support so as to allow them to continue to combat the Turkish threat.

Weary of the long struggle with the Duchy of Pomerania, he abdicated in 1470 in favour of his younger brother Albert Achilles, he retired to the Bayreuth Principality and died one year later in Neustadt an der Aisch.