William Hagarty O'Leary (1836 - 15 February 1880) was an Irish medical doctor and politician.
He became a fellow of the Royal College of Surgeons in 1871.
He was elected Member of Parliament for Drogheda in 1874 and sat for the seat as a Home Ruler until his death in 1880.
A contemporary remarked of him that "Mr. O'Leary spoke very eloquently, though somewhat floridly.
[1] This article about a Member of the Parliament of the United Kingdom, for a constituency in Ireland between 1801 and 1922 is a stub.