Titles:
Knight of the Garter
Earl of Essex (1374 m)
Earl of Buckingham (1377 cr)
Duke of Gloucester (1385 cr - 1st)

Thomas of Woodstock, 1st Duke of Gloucester (January 7, 1355 – September 8 (or 9), 1397) was the thirteenth and youngest child of King Edward III of England and Queen Philippa. He was the fifth of the five sons of Edward III who survived to adulthood, and like his brothers, he and his descendants were active participants in the struggle for the English Crown known as the Wars of the Roses. Thomas was murdered in Calais in 1397 on behalf of his nephew, King Richard II of England.

Thomas was born after two short-lived sons, one of whom had also been baptised Thomas. He was born at Woodstock Palace in Oxfordshire. He married Eleanor de Bohun in 1376, and inherited the title Earl of Essex from his father-in-law, Humphrey de Bohun, 7th Earl of Hereford. Woodstock's wife's younger sister, Mary de Bohun, was subsequently married to Henry "Bolingbroke," who eventually became Henry IV of England.

At the age of 22, in 1377, Woodstock was created Earl of Buckingham. In 1385 he received the title Duke of Aumale, and at about the same time was created Duke of Gloucester.

Thomas and his wife had one son and four daughters. Following his murder (probably on the orders of his nephew, King Richard II of England), at Calais in 1397, his title was forfeit and did not pass to his son, Humphrey.

His eldest daughter, Anne of Gloucester, married into the powerful Stafford family, who were Earls of Stafford and Dukes of Buckingham, and four generations after Thomas, the disposition of the de Bohun estates may have been a motivating factor in the involvement of Henry Stafford, 2nd Duke of Buckingham in plots against the crown during the period of Richard III.