Jan II the Mad also known as the Bad, the Wild or the Cruel (Polish: Jan II Szalony or Zly or Dziki or Okrutny; 16 April 1435 – 22 September 1504), was a Duke of Zagan-Przewóz since 1439 (with his brothers as co-rulers until 1449), from 1449 Duke of Przewóz (as co-ruler of his younger brother), during 1461–1468 and briefly in 1472 Duke of Zagan and during 1476–1488 Duke of half-Glogów (the Duchy was finally reunited in 1480).
He was the fourth and youngest son of Duke Jan I of Zagan by his wife Scholastika, daughter of Rudolf III, Duke of Saxe-Wittenberg and Elector of Saxony.