Alexander Arbuthnot (7 May 1768 – 9 January 1828) was Bishop of Killaloe and Kilfenora in the then-established Church of Ireland.He was born in Rockfleet Castle, County Mayo, Ireland, the son of John Arbuthnot of Rockfleet. Among his siblings were the Right Honourable Charles Arbuthnot and General Sir Thomas Arbuthnot.Arbuthnot was ordained a priest at Limerick on 2 November 1794, made vicar of Annaghdown and Killascobe in 1801 and rector of Crossboyne and Kilcoleman in 1808.