Sir Ralph Delaval, 1st Baronet (13 October 1622 – 29 August 1691) of Seaton Delaval, Northumberland was an English landowner and politician who sat in the House of Commons at various times between 1659 and 1685. Delaval was the son of Robert Delaval of Seaton Delaval. He matriculated at Queen's College, Oxford on 15 June 1638, aged 16 and was admitted to Lincoln's Inn in 1639. He was High Sheriff of Northumberland in 1649. Delaval developed the family's commercial interests at Seaton Delaval by building a harbour and sluice gates at nearby Hartley Pans, which came to be known as Seaton Sluice.