The Battle of Bryn Glas (also known as the Battle of Pilleth) was a battle between the Welsh and English on 22 June 1402, near the towns of Knighton and Presteigne in Powys, Wales. It was part of the Glyndŵr Rising of 1400-1415. It was an important victory for the Welsh under Owain Glyndŵr, as it resulted in the prolongation of the Welsh war of independence and the destabilisation of English politics for several years afterward.