Saint Malachy (Middle Irish: Máel Máedóc Ua Morgair, Modern Irish: Maelmhaedhoc Ó Morgair) (1094 – 2 November 1148) was the Archbishop of Armagh, to whom were attributed several miracles and a vision of the identity of the last 112 Popes (see Prophecy of the Popes). He was the first Irish saint to be canonised by a pope.

St Malachy, whose family name was Ua Morgair, was born in Armagh in 1094. St. Bernard describes him as having noble birth. He was baptized Máel Máedóc (a name which has been anglicised to Malachy) and was trained under Imhar O'Hagan, subsequently Abbot of Armagh. After a long course of studies he was ordained priest by St Cellach (Celsus) in 1119. To perfect himself in sacred liturgy and theology, he proceeded to Lismore, where he spent nearly two years under St Malchus. He was then chosen Abbot of Bangor, in 1123. A year later, he was consecrated Bishop of Down and Connor, and, in 1132, he was promoted to the primacy of Armagh. St Bernard gives us many interesting anecdotes regarding St Malachy, and highly praises his zeal for religion both in Connor and Armagh. In 1127 he paid a second visit to Lismore and acted for a time as confessor to Cormac MacCarthy, Prince of Desmond. While Bishop of Down and Connor, he continued to reside at Bangor, and when some of the native princes sacked the two dioceses of Down and Connor, he brought the Bangor monks to Iveragh, County Kerry, where they were welcomed by now King Cormac. On the death of St Celsus (who was buried at Lismore in 1129), St Malachy was appointed Archbishop of Armagh, 1132, which dignity he accepted with great reluctance. Owing to intrigues, he was unable to take possession of his See for two years; even then he had to purchase the Bachal Isu (Staff of Jesus) from Niall, the usurping lay-primate.