The monastery was founded in the 7th century by Saint Colman Mac Duagh. According to legend, he chose this spot after his belt fell to the ground, which he saw as a divine sign. The land was donated by his nephew, King Guaire Aidne mac Colmáin of Connacht. In the 12th century, Kilmacduagh became the center of a new bishopric, the Bishopric of Kilmacduagh. Later, in the 13th century, it became an Augustinian abbey. Under the reign of the English King Henry VIII, monasteries were officially dissolved throughout Ireland in the 16th century. In 1750, the independent Bishopric of Kilmacduagh was merged with that of Kilfenora. By 1814, the religious function had been completely taken over by the new Church of St. Colman in nearby Gort, after which the old buildings were left to their fate.