St Mullins is a village, civil parish and townland on the eastern bank of the River Barrow in the south of County Carlow, Ireland. It is less than 2 km off the R729 regional road.

The Book of Mulling or less commonly, Book of Moling, is an Irish pocket Gospel Book from the late 8th or early 9th century. The text collection includes the four Gospels, a liturgical service which includes the "Apostles' Creed", and in the colophon, a supposed plan of St. Moling's monastery enclosed by two concentric circles.