Henry de Percy, 1st Baron Percy of Alnwick (25 March 1273 – October 1314) was a medieval English magnate.
He fought under King Edward I of England in Wales and Scotland and was granted extensive estates in Scotland, which were later retaken by the Scots under King Robert I of Scotland.
He added Alnwick to the family estates in England, founding a dynasty of northern warlords.
He rebelled against King Edward II over the issue of Piers Gaveston and was imprisoned for a few months.
After his release, he declined to fight under Edward II at the Battle of Bannockburn, remaining at Alnwick, where he died a few months later, aged 41.