John Christian of Brieg (Polish: Jan Chrystian Brzeski; German: Johann Christian von Brieg; Ohlau, 28 August 1591 – Osterode in Ostpreußen (today Ostróda), 25 December 1639), was a Duke of Brzeg–Legnica–Wołów (since 1602; with his brother as co-ruler in Legnica and Wołów until 1612; in Oława since 1605).
He was the second but eldest surviving son of Joachim Frederick, Duke of Brzeg–Oława–Legnica–Wołów, by his wife Anna Maria, daughter of Joachim Ernest, Prince of Anhalt. In his baptism, who was realized two weeks after his birth, on 14 September, he received the names of both uncles: John George of Oława and Christian of Anhalt.
Joachim Frederick died on 25 March 1602, leaving his two sons as the heirs of his domains. John Christian had eleven-years and his younger brother George Rudolf had only seven, the regency of the Duchies was taken by their mother, the Dowager Duchess Anna Maria (who was the reign Duchess of Oława as her Oprawa wdowia). After Anna Maria's death in 1605, the regency was taken by the paternal aunt of the young Dukes (and only surviving sibling of the late Joachim Frederick), Elisabeth Magdalena of Brieg and her husband, Charles II of Poděbrady, Duke of Ziębice–Oleśnica.
During some time, John Christian live in Krosno Odrzańskie (German: Crossen an der Oder), where he met his first wife, Dorothea Sybille of Brandenburg.