Humphrey, Duke of Gloucester (1390 - February 23, 1447) was the fifth son of King Henry IV of England by his first wife, Mary de Bohun.

The place of his birth is unknown, but he was named after his maternal grandfather, Humphrey de Bohun, 7th Earl of Hereford. He was created Duke of Gloucester in 1414, and in about 1422 he married Jacqueline, Countess of Hainaut and Holland, daughter of William VI . Through this marriage Humphrey assumed the title "Count of Holland, Zeeland and Hainault". The marriage was annulled in 1428, and Jacqueline died (disinherited) in 1436. Meanwhile, Humphrey remarried, his second wife being his former mistress, Eleanor Cobham . On the death of his brother, King Henry V of England, in 1422, Humphrey became regent of the kingdom and protector to his young nephew, King Henry VI. In 1441, Eleanor was tried and convicted of practising witchcraft against the king in an attempt to retain power for her husband. She died in prison. There were no surviving children from either of Duke Humphrey's marriages.

Following his wife's conviction, Humphrey himself was arrested on a charge of treason. He died, or was assassinated, at Bury St Edmunds in Suffolk, a few days later. His name lives on in "Duke Humfrey's Library", part of the Bodleian Library in Oxford, to which Humphrey donated the nucleus of its collection.