Henry of Grosmont, 1st Duke of Lancaster, 4th Earl of Leicester and Lancaster, KG (c. 1310 – March 23, 1361), also Earl of Derby, is a member of the English nobility in the furteenth century, and a prominent English diplomat, politician, and soldier.

The son and heir of Henry, 3rd Earl of Lancaster, and Maud Chaworth, he becomes one of Edward III's most trusted captains in the early phases of the Hundred Years' War and distinguishes himself with victory in the Battle of Auberoche.

He is a founding member and the second Knight of the Order of the Garter in 1348, and in 1351 is created duke.

Grosmont is also the author of the book Livre de seyntz medicines, a highly personal devotional treatise.

He is remembered as one of the founders and early patrons of Corpus Christi College, Cambridge, which is established by two of the guilds of the town in 1352.