Lady Katherine Percy (18 May 1423 – c.?1475) was the daughter of Henry Percy, 2nd Earl of Northumberland and Lady Eleanor Neville.
Her maternal grandparents were Ralph Neville, 1st Earl of Westmorland and his second wife Joan Beaufort, a legitimized daughter of John of Gaunt.
She married Edmund Grey, 1st Earl of Kent and had seven children:
Mary Grey (1440–1474);
Anthony Grey (1446–1480), married Eleanor Woodville, daughter of Richard Woodville, 1st Earl Rivers;
Elizabeth Grey (d.
1472), married Sir Robert Greystoke;
Anne Grey (b.
1450), married John Grey, 8th Baron Grey de Wilton;
George Grey, 2nd Earl of Kent (1454–1505), married Anne Woodville;
John Grey (1455–1484);
Edmund Grey (b.