Neath Abbey (Welsh: Abaty Nedd) was a Cistercian monastery, located near the present-day town of Neath in South Wales, UK. It was once the largest abbey in Wales. Substantial ruins can still be seen, and are in the care of Cadw. Tudor historian John Leland called Neath Abbey "the fairest abbey of all Wales." Neath Abbey is also the name of an area of Neath near to the abbey ruins.