Arthur Grey, 14th Baron Grey de Wilton (1536–1593) was a baron in the Peerage of England, remembered mainly for his memoir of his father, and for participating in the last defence of Calais.
Arthur Grey was the eldest son of William Grey, 13th Baron Grey de Wilton and Mary, daughter of Charles Somerset, 1st Earl of Worcester. He was a Knight and he was recorded as being Lord Lieutenant of Buckinghamshire on two separate occasions, in both 1569 and 1587, though it is not recorded if he held that title for all the years in between. He probably went with his father to Guisnes in 1553; certainly he was there when the French declared war in 1557; his eye-witness account of his father's last desperate defence of Guisnes, after Calais itself has fallen, remains the best source for the episode. Like his father he became a hostage but was ransomed a year later. He succeeded his father as 14th Baron in 1562; the family fortune was by then much reduced by the heavy ransom required to free his father. Elizabeth I, however, restored the property forfeited by his father for his part in the Lady Jane Grey affair.
In 1580, he recruited a force of 6,000 and was sent as Lord Deputy of Ireland to quell the Second Desmond Rebellion, replacing the notoriously brutal Sir William Pelham. His first main encounter was when he led an army of about 3,000 in the Battle of Glenmalure, County Wicklow in August, where he was slaughtered by Fiach McHugh O' Byrne, with casualties of 800. Later in the same year he led a force of 800 to Ard na Caithne (Smerwick) in County Kerry where he massacred 600 Irish/Italian/Spanish troops who surrendered, a notorious incident known as the Siege of Smerwick. According to some versions of this event, Grey promised the garrison their lives in return for their surrender, a promise which he broke – this resulted in the Irish proverb 'Grey's faith'.