Sir Thomas Shirley (1564 – c. 1634) was an English soldier, adventurer and politician who sat in the House of Commons at various times between 1584 and 1622. His financial difficulties drove him into privateering which culminated in his capture by the Turks and later imprisonment in the Tower of London.
Thomas Shirley was the eldest son of Sir Thomas Shirley of Wiston, Sussex, and Anne Kempe, the daughter of Sir Thomas Kempe (d. 7 March 1591) of Olantigh in Wye, Kent.Sir Anthony Shirley and Sir Robert Shirley were his younger brothers.
Shirley matriculated at Hart Hall, Oxford in 1579, but left the university without taking a degree. In 1584 he was elected Member of Parliament for Steyning. He went on military service with his father and brother in the Low Countries in 1585, and later saw some in Ireland. He was knighted at Kilkenny in Ireland by the lord deputy, Sir William Fitz-William, on 26 October 1589. Shirley later came to the court. In the summer of 1591 he made a secret marriage to one of Queen Elizabeth's maids of honour and when the queen heard of it, she promptly committed him to the Marshalsea Prison. He remained in prison till the spring of 1592. In 1593 he was elected MP for Steyning again. In the same year he saw service with the rank of captain in the Low Countries again.
Shirley was beginning to suffer from hopeless embarrassment because of his father's increasing financial difficulties. To secure a livelihood, he decided to fit out a privateering expedition to attack Spanish merchandise. He handed over his company at Flushing to Sir Thomas Vavasour, a relation of his wife, and in the summer of 1598 sailed into the English Channel, and seized four 'hulks' of Lübeck which were reputed to be carrying Spanish goods. He may have made some of his attacks with the Queen's ship Foresight, which he commanded in 1599. The costs and returns were high. A ship that Shirley captured while returning from San Domingo laden with sugar, was valued at £4,700. In April 1600, Shirley offered the Earl of Nottingham £600 for his tenth share in two ships which he brought into Plymouth and said he had already paid £2,000 for 'the company's thirds'. In October 1600 Shirley was brought before the Admiralty court for seizing a ship from Hamburg which had a cargo belonging to some Dutch merchants and Lord Cobham had to intervene on his behalf. He was also coming under attack from his creditors for in July 1600 some supporters of Sir Richard Weston broke into his father's house at Blackfriars and threatened the Shirleys, father and son, demanding payment. In 1601 his father required the borough seat of Steyning. Shirley was elected MP for both Bramber and Hastings and chose to sit for Hastings. In 1602 he renewed his privateering adventures, and pillaged 'two poor hamlets of two dozen houses in Portugal.'