Ralph George Algernon Percy, 12th Duke of Northumberland,, styled Lord Ralph Percy until 1995, is a British hereditary peer and rural landowner and current head of the House of Percy.

The Percy family is an English noble family. They were among the most powerful noble families in Northern England for much of the Middle Ages. The noble family is known for its long rivalry with the House of Neville, another family powerful in northern England during the 15th century. The Percy-Neville feud led to the Wars of the Roses, at the time known as the Civil Wars, in England.