Sir John Donne (probably born in 1420s – 1503) was a Welsh courtier, diplomat and soldier, a notable figure of the Yorkist party. In the 1470s he commissioned the Donne Triptych, an triptych altarpiece by Hans Memling now in the National Gallery, London. It contains portraits of him, his wife Elizabeth and a daughter. He may well have been related to the Jacobean poet John Donne, although not as a direct ancestor, as he had no Donne grandchildren.
The Donnes of Kidwelly, Carmarthenshire were a distinguished family ("Dwnn" in Welsh). His father Griffith (Gruffydd) reputedly fought at the Battle of Agincourt in 1415 and certainly in many other French campaigns; he was Lieutenant of Cherbourg in 1424. His mother was Joan Scudamore, a grandchild of Owain Glyndŵr, the last independent Prince of Wales, who disappeared into hiding in 1412. John Donne was born in France, "in parts of Picardy", probably in the 1420s.
Donne was their third son who entered, probably in his late teens, the service of the Duke of York, father of Edward IV. He may have done so through the patronage of the leading Yorkist in South Wales, William ap Thomas, also an Agincourt veteran and father of Donne's contemporary William Herbert, 1st Earl of Pembroke (1423-1469). Donne is recorded as having fought in France for the Duke, which must have been before 1447. It is from this and his apparent age in the Memling that his birth in the 1420s is estimated. He also fought for the Duke in England, and in the late 1440s in Ireland.