Sir Henry Dudley (1517–1568) was an English soldier, sailor, diplomat, and conspirator of the Tudor period.
Born in Dudley Castle, Staffordshire, Henry Dudley was the second son of John Sutton, 3rd Baron Dudley. His mother was Cicely, a daughter of Thomas Grey, 1st Marquis of Dorset. Dudley was the first cousin of Henry Grey, 1st Duke of Suffolk, the father of Lady Jane Grey, and the second cousin once removed of John Dudley, 1st Duke of Northumberland. He is not to be confused with the youngest of Northumberland's sons, also named Henry Dudley, who married Margaret, the daughter of Lord Chancellor Thomas Audley.
Dudley became a monastic auditor under Thomas Cromwell in 1535, and then a soldier serving in Ireland under his uncle Leonard Grey in 1536, and in Scotland from 1540-3. Dudley fought gallantly during the siege of Boulogne in 1544, and was made a Captain early in 1545 under Lord Clinton. It was about 1535–1545, probably at Boulogne that he married the daughter of Christopher Ashton, (b 1493) who was born about 1519 and who bore him a son, Roger Dudley.
He was promoted to Vice Admiral of the Narrow Seas 1553 when Lord Clinton was Lord Admiral, and knighted at Hampton Court on 11 October 1551. A close associate of his second cousin, the Duke of Northumberland, he was arrested on 25 July 1553 at Calais. The duke had sent him to France around 13 July 1553 to confer with King Henry II regarding French support in the event of an Imperial intervention in England. Dudley was imprisoned in the Tower of London, but pardoned by Queen Mary on 18 October 1553.