Margaret de Clare, Countess of Gloucester, Countess of Cornwall (12 October 1293 - 9 April 1342) was an English noblewoman, heiress, and the second eldest of the three daughters of Gilbert de Clare, 6th Earl of Hertford and his wife Joan of Acre, making her a granddaughter of King Edward I of England. Her two husbands were Piers Gaveston and Hugh de Audley, 1st Earl of Gloucester.