Ferns Abbey (Irish: Mainistir Aodháin) is a ruined Augustinian abbey in Ferns, County Wexford, Ireland. Likely built on the site of an early Christian monastic site founded by Máedóc of Ferns, the standing remains were built by Diarmait Mac Murchada c.1160. The abbey was suppressed on 7 April 1539. The abbey was claustral in layout, and features an unusual tower that is half square, half round. Partially rebuilt in 1846, many original architectural elements were damaged at this time.