Allen Edward Buchanan (born 1948) is a moral, political and legal philosopher.

As of 2022, he held multiple academic positions: Laureate Professor of Philosophy at the University of Arizona, Distinguished Research Fellow at Oxford University, Visiting Professor of the philosophy of international law at the Dickson Poon School of Law at King's College, London, and James B. Duke Professor Emeritus at Duke University.

Dr. Buchanan's initial academic job was at the University of Minnesota, where he was promoted to associate professor of philosophy with tenure.

[2][3] Earlier in his career, Buchanan served as a staff philosopher for the President's Commission on Medical Ethics; served on the Advisory Council for the National Human Genome Research Institute; and was a Fellow at the National Humanities Center.

He has written six books covering such topics as Marx, applied ethics (especially bio-medical ethics), social justice, and international justice, including the foundations of international law.