St Gwenllwyfo's Church is a 19th-century parish church near the village of Dulas, in Anglesey, Wales. It was built between 1854 and 1856 to replace an earlier church in the parish, also dedicated to St Gwenllwyfo, which needed repair and had become too small for its congregation. The new church was built nearer to the Llys Dulas estate, whose owner contributed £936 towards the total cost of £1,417, rather than near the area where many of the parishioners lived. In 1876, Sir Arundell Neave (who had married into the family that owned Llys Dulas) donated 27 panels of 15th and 16th-century stained glass that had once belonged to a Flemish monastery.