Henry Beaufort, 3rd Duke of Somerset (1436 - 1464) was an important Lancastrian military commander during the English Wars of the Roses. (Some number him 2nd Duke, since the title was re-created for his father after his uncle died.)

Somerset was the son of Edmund Beaufort, 2nd Duke of Somerset and Eleanor Beauchamp, daughter of Richard Beauchamp, Earl of Warwick. Thus he was first cousin to Margaret Beaufort and to Richard Neville, Earl of Warwick, and uncle to Henry Stafford, 2nd Duke of Buckingham.

Somerset fought at the First Battle of St Albans (1455), where he was seriously wounded and his father was killed. He was one of the principal Lancastrian commanders at the Battle of Wakefield, the Second Battle of St Albans, and the Battle of Towton, fleeing into Scotland after the last of these.

From Scotland he forayed into France to negotiate for help, and into England on some short border raids and castle occupations. After surrendering at the end of one castle siege, he indicated his willingness to make peace with King Edward. The king needed to win over some of the Lancastrian commanders to help secure his hold on the throne, and so pardoned Somerset in 1462, restoring his forfeited lands and titles.

For the next year or so Somerset remained close to Edward, attending his court and giving him military advice. But at the end of 1463 he slipped back over to the Lancastrian side, hurried north and started raising troops. He held out in the far north of England until the next May (1464), when he was defeated at the Battle of Hexham, and beheaded shortly afterwards.

Somerset left no legitimate children. He did have an illegitimate son, Charles Somerset, 1st Earl of Worcester, from whom descend the Earls and Marquesses of Worcester and later the Dukes of Beaufort.