Knockmoy Abbey (Irish: Mainistir Chnoc Muaidhe),[2] also known as The Monastery of the Hill of Victory (Latin: Monasterium Collis Victoriæ);[3] and as Porta Magna (English: Great Door)[4] and Teampollandorusmoir (English: The Chapel with the Big Door)[4] after the dissolution of the monasteries,[5] is a ruined Cistercian abbey located in Abbeyknockmoy, County Galway, Ireland.

[4] Knockmoy was first plundered in either 1202 or 1203 by William de Burgh, and it was subsequently raided several other times, the next occasion being in 1228.

[7] On 24 May 1542, following the dissolution of the monasteries, Hugh O'Kelly, the abbot in commendam surrendered the abbey to Henry VIII.

The walls of this building are not bonded with the rest of the monastery, and it is likely of fourteenth century construction.

In the eastern end of the refectories south wall is an opening 2.7 metres (9 ft) wide, which would have featured steps leading up to a rostrum.

The walls here are in very poor condition, and having been reshaped several times to serve as a fence, give no indication as to the original placement of the windows.

[15] To the west of the cloister were buildings two storeys tall, which housed the lay brothers of the monastery.

[20] Long exposed to the elements, in the 1980s the Office of Public Works weather-proofed the segment of the abbey which houses them.