Kieran Andrew O'Reilly SMA KC*HS (born 8 August 1952) is an Irish Roman Catholic prelate who has served as Archbishop of Cashel and Emly since 2015.

O'Reilly became a permanent member of the Society of African Missions by professing perpetual vows on 10 April 1977, and was ordained a priest on 17 June 1978.

He was then appointed Professor of Biblical Studies at the major seminary of Saints Peter and Paul in Ibadan, Nigeria, where he taught until 1988.

[1][6] He was a popular and accessible bishop with one only public controversy in August 2014, when men were invited to apply for a restoration of the Permanent Diaconate in the diocese.

[7] Women, "who do the majority of the work in the parishes", had been "hurt and greatly disappointed" by O'Reilly's male-only invitation, forcing him to decide to "not now proceed with the introduction of the permanent diaconate at this time".