The Battle of Ōhaeawai, part of the Flagstaff War, was fought in July 1845 at Ōhaeawai in Northland, New Zealand. The battle was between British forces and their allies from the local Ngāpuhi tribe of Māori on one side, and other Ngāpuhi, led by Te Ruki Kawiti, a prominent rangatira (chief), on the other side. The battle was notable for establishing that an appropriately built fortified pā could withstand bombardment from cannon fire, with a frontal assault by soldiers suffering heavy casualties.

Ōhaeawai is a small village at the junction of State Highway 1 and State Highway 12 in the Far North District of New Zealand, some 250 km (160 mi) from Auckland. The town of Kaikohe is 10.4 km (6.5 mi) to the west, and the Bay of Islands is a short drive to the east.