William Ferrers, 3rd Baron Ferrers of Groby (1333–1371) was a Leicestershire-based nobleman in fourteenth-century England who took part in some of the major campaigns of the first part of the Hundred Years' War. The eldest of two sons to Henry Ferrers, 2nd Baron Ferrers of Groby (d. 1343), and Isabel de Verdun, daughter of Theobald de Verdun, 2nd Baron Verdun, William was ten years old when he succeeded his father to the Barony.[2]