|Born||19 March 1958|
|Alma mater||Keble College, Oxford, London School of Economics|
|Employer||London School of Economics, University of Pennsylvania|
Brendan O'Leary (born 19 March 1958) is an Irish political scientist, who is Lauder Professor of Political Science at the University of Pennsylvania. He was formerly a professor at the London School of Economics. In 2009-10 he was the second Senior Advisor on Power-Sharing in the Standby Team of the Mediation Support Unit of the Department of Political Affairs of the United Nations.
Brendan O'Leary was born in Cork, Ireland. His childhood and teenage years were mostly spent in Nigeria, Sudan, and Northern Ireland. He is a graduate of Keble College, Oxford University, where he was the holder of an Open Scholarship, and received a first class honors degree in Philosophy, Politics and Economics (1981). He was tutored by Larry Siedentop, the scholar of Tocqueville and critic of the democratic underdevelopment of the European Union, and by the economist Paul Collier. O'Leary wrote his PhD thesis at the London School of Economics & Political Science. It was examined by Ernest Gellner and Nicos Mouzelis, and won the Robert McKenzie Memorial Prize. It was subsequently published as The Asiatic Mode of Production: Oriental Despotism, Historical Materialism and Indian History. 
Before coming to Penn, O'Leary was on the faculty of the London School of Economics and Political Science between 1983 and 2003, where he had been Professor of Political Science, head of its Government Department, and an elected Academic Governor. Between 2012 and 2014 he is also Professor of Political Science at Queen's University Belfast.
O'Leary is the author of numerous influential books about the Northern Ireland conflict, many of them co-authored with John McGarry, whom he met when they both attended Saint MacNissi’s College. McGarry and O'Leary's Policing Northern Ireland: Proposals for a New Start (Blackstaff Press, 1999) is considered to have had a significant influence on the work of the Independent Commission on Policing for Northern Ireland. He has been an international advisor to the Kurdistan National Assembly, responsible for advising on the constitutional reconstruction of Iraq and Kurdistan, with special responsibility for federal arrangements and electoral laws. He has also advised the United Nations, the European Union and the UK's Department for International Development. Previously, he was a policy advisor to the British Labour Party, and political advisor to Mo Mowlam and Kevin McNamara during their respective spells as Shadow Secretary of State for Northern Ireland. In the course of his career he has supervised more than thirty doctoral dissertations, including those of political scientists Stefan Wolff and Tristan James Mabry.
In both his own writings and those with John McGarry, O'Leary has long backed consociationalism as a method of conflict management for Northern Ireland, and is supportive of the Good Friday Agreement. In this regard, Arend Lijphart has been a significant influence on O'Leary's work. In 2009, a book entitled Consociational Theory: McGarry and O'Leary and the Northern Ireland Conflict was published, edited by Rupert Taylor. He is also the author of How to Get Out of Iraq with Integrity (University of Pennsylvania Press, 2009). Recent books include "Power-Sharing in Deeply Divided Places" (co-edited with J. McEvoy), "Divided Nations and European Integration" (co-edited with T.Mabry, J.McGarry and M. Moore), and "Courts and Consociations" (coauthored with Christopher McCrudden).
In 2009, Rupert Taylor published Consociational Theory: McGarry and O'Leary and the Northern Ireland Conflict, Routledge, a symposium devoted to Professor O'Leary's work with his colleague Professor John McGarry. The collection is preceded by a lengthy statement by McGarry and O'Leary, and concludes with their reply to the 16 contributions which discuss their work.
Research Interests: Power-sharing systems, especially in consociations and pluralist federations. Nationalism; national and ethnic conflict-regulation; national self-determination. National, ethnic and communal violence and the security sectors of divided places. Democracy, democratization and electoral systems. Despotisms: Ancient and Modern. Nations, States and Empires: past and present. Constitutional design debates: especially regarding executives; legislatures; electoral systems; minority, group, linguistic, ethnic, religious, autonomy and national self-determination rights, and the division and sharing of powers in federations and confederations (including the EU). Secular and theocratic doctrines. Empirical conflict research: Iraq's federalization; the Break-up of Sudan; the Irish peace process; Kurdish politics. The Crises of the European Union.
- Peter Kingston (1996-06-18). "Celebrity scholars, number 23: Brendan O'Leary". The Guardian education section. p. 4.
- Brendan O'Leary, Lauder Professor of Political Science. Penn Arts & Sciences. Retrieved 26 January 2014
- "Brendan O'Leary". Penn Program in Ethnic Conflict. Retrieved 2007-12-08.
- McDermott, Peter (2009-02-11). "Ethnic conflict specialist proposes Iraq withdrawal". Irish Echo. Retrieved 2009-04-02.[dead link]
- Barry White (1999-09-18). "Patten...finding the gems in the detail". Belfast Telegraph.
- "Brendan O'Leary, CV" (PDF). University of Pennsylvania Political Science Department. Retrieved 2008-08-15.
- O'Leary, Brendan (1989). "The limits to coercive consociationalism in Northern Ireland". Political Studies 37 (4): 562–587. doi:10.1111/j.1467-9248.1989.tb00289.x.
- McGarry, John; O'Leary, Brendan (2006). "Consociational theory, Northern Ireland's conflict, and its Agreement. Part 1: What consociationalists can learn from Northern Ireland" (PDF). Government and Opposition 41 (1): 43–63. doi:10.1111/j.1477-7053.2006.00170.x.
- Taylor, Rupert, ed. (2009). Consociational Theory: McGarry and O'Leary and the Northern Ireland Conflict. London: Routledge. ISBN 0-415-42913-7.