The Battle of Heavenfield was fought in 633 or 634 between a Northumbrian army under Oswald of Bernicia and a Welsh army under Cadwallon ap Cadfan of Gwynedd. It was a decisive Northumbrian victory.

Following the Battle of Hatfield Chase on October 12, 632 (or 633), during which the Northumbrian king Edwin was killed by the invading Welsh and Mercians, Northumbria was split between its two sub-kingdoms, Bernicia and Deira, and exposed to the devastation of Cadwallon's invading army. The king of Bernicia, Eanfrith, was killed by Cadwallon after attempting to negotiate peace.

Eanfrith's brother, Oswald, then returned from exile in Dalriada and, with the aid of a force of Scots, marched against Cadwallon and confronted him near Hexham, by Hadrian's Wall. Before the battle, it is said that he raised a cross and prayed for victory alongside his troops, and afterward the site was known as Heavenfield. Although the Welsh probably had superior numbers, they were defeated and pursued for miles by the triumphant Northumbrians. Cadwallon himself was killed.

After the battle, Oswald reunited Deira with Bernicia and became king of all Northumbria.