Sir Henry Killigrew (c. 1528 – 1603) was an English diplomat and ambassador in the sixteenth century. He was several times employed by Elizabeth I in Scottish affairs and served as one of the English appointees to the Council of State of the Netherlands in the United Provinces in 1586 and 1587-1589. Member of Parliament for Newport & Launceston in 1553, Saltash in 1563, Truro in 1571-2.
He was the fourth son of John III Killigrew (d.1567) of Arwenack, the first Governor of Pendennis Castle, of an old Cornish family, by his wife Elizabeth Trewenard, second daughter of James Trewenard of Trewenard. He was probably educated at Cambridge, but there is no definite information on the point. Killigrew served as a gentleman in the household of John Dudley, Duke of Northumberland, and became a lifelong follower of the Dudleys. On 18 February 1553 he was returned member of parliament for Newport-juxta-Launceston. He assisted Sir Peter Carew in escaping to the continent in January 1554, and during the remainder of Queen Mary of England's reign appears to have been in exile. Killigrew was at Paris in July 1556, when he was described by the English authorities as a rebel. From a French base, he and his brother Peter engaged in piracy. In August 1557, Henry was present at the Battle of St. Quentin, where Sir James Melville stated of him that "Harry Killygrew, an Englis gentilman, my auld friend," held his horse while he got his wound dressed after his escape. Killigrew was recalled to England on the accession of Elizabeth, and she employed him on various diplomatic missions, including one to Germany in connection with negotiations for a defensive league. In July 1559 he went for a short time to assist Nicholas Throckmorton in France.