Ardtole Church is a fifteenth century ruined church standing on a hill overlooking the sea and the Isle of Man, 1.2km north-east of the town of Ardglass in County Down, Northern Ireland. The church is dedicated to St Nicholas, the patron saint of sailors. The structure is of a characteristic Anglo-Irish parish church of the Middle Ages. In 1791 a cross-decorated slab of the Early Christian period was found, showing that perhaps the site has a longer tradition than the surviving remains would suggest. A souterrain was also found south of the church.

The Church sat halfway between the Anglo-Norman settlers and traders of Ardglass and the native Irish of the surrounding area, but was used by both sets of people until the fifteenth or sixteenth century. According to tradition some people from Ardglass found the chieftain of the MacCartans in a drunken sleep and fastened his hair to some briars. He avenged this affront with a massacre of the townsmen gathered together for mass in Ardtole Church. This disaster led to the abandonment of the building as a place of worship for Ardglass, probably in the sixteenth century.