Llanthony Priory is a picturesque former Augustinian priory, located in the Black Mountains area of the Brecon Beacons National Park in South Wales.

Founded in the early 1100's by William de Lacy, it was a victim of Henry VIII's Dissolution of the Monasteries, and today stands as a majestic ruin within the rugged yet beautiful Vale of Eywas.

The priory had a sister monastery in Gloucester, also called Llanthony Priory (Llanthony Secunda).