Myles William Patrick O'Reilly (1825 in Balbriggan, Ireland – 6 February 1880 in Dublin, Ireland) was a Catholic soldier, MP and publicist. He was the only son of William O'Reilly of Thomastown (Knock Abbey) Castle, County Louth and was educated at Ushaw College in County Durham and at London University. He entered the Middle Temple in 1848. He succeeded his father to Knock Abbey Castle in 1844 and was selected High Sheriff of Louth for 1848–49.