Llangristiolus is a village and community in the middle of Anglesey, Wales, southwest of Llangefni, and is named after Saint Cristiolus. The River Cefni flows through the village. The village is within a mile of the A5 and A55 roads. The village of Rhostrehwfa is in the community. The church of St Cristiolus, Llangristiolus, dates from the 12th century.