Lionel of Antwerp, 1st Duke of Clarence, jure uxoris 4th Earl of Ulster and 5th Baron of Connaught, KG (November 29, 1338 – October 7, 1368) is the third son, but the second son to survive infancy, of Edward III of England and Philippa of Hainault.

He is so called because he was born at Antwerp in Flanders.

Prince Lionel, born of a Flemish mother and the grandson of William I, Count of Hainaut, grows to be nearly seven feet in height and has an athletic build.