Josiah Ober is an American historian of ancient Greece and classical political theorist. He is Tsakopoulos-Kounalakis Professor in honor of Constantine Mitsotakis, and professor of classics and political science, at Stanford University. His teaching and research links ancient Greek history and philosophy with modern political theory and practice.
He has received fellowships from numerous institutions, including the American Council of Learned Societies (1989–90); the National Endowment for the Humanities (1997); Center for Advanced Study in the Behavioral Science (2004-5). He delivered the 2002-2003 Sigmund H. Danziger, Jr. Memorial Lecture in the Humanities at the University of Chicago and the 2019 Sather Lectures University of California, Berkeley.
Ober was a student of the distinguished American ancient Greek historian Chester Starr, and has been the teacher of many scholars, such as the classicist John Ma, ancient Greek historian Emily Mackil, and the political theorist Ryan Balot.
Ober's Mass and Elite in Democratic Athens won the prestigious Goodwin Award in 1989. Some early work was criticized by Mogens Herman Hansen for overemphasizing the ideological aspect of Athenian democracy against its institutional dimension, and P.J. Rhodes accused him of abandoning scholarly impartiality in favour of democratic advocacy. In a review of The Rise and Fall of Classical Greece for New Left Review, the Marxist classicist Peter Rose concluded that Ober had produced 'an eccentric, at times intriguing, but deeply flawed work of history, which ultimately tells us more about the ideology of the Stanford classics department than it does about ancient Greece'.
On the whole, however, Ober's work has been well received. For example, Paul Cartledge called Mass and Elite in Democratic Athens 'a seminal work',  Jennifer Roberts called Political Dissent in Democratic Athens 'a major contribution to a dialogue of enormous import'. Melissa Lane writes: "Ober draws on empirical evidence about the ancient world in the service of normative political theory, and in so doing sheds light not just on Athens but on the creation and operation of democratic institutions." Professor of politics Danielle Allen, classicist and political theorist, also praises Ober's "Democracy and Knowledge' in The New Republic (2008). Mimis Chrysomalis's review of The Rise and Fall of Classical Greece CritCom notes that in this 'signficant resource for scholars of classical antiquity, political science, and economic history' Ober 'offers a novel perspective on how economic performance was connected to . . . democratic institutions.'  Professor of law Adriaan Lanni's review praises Rise and Fall as part of the 'exciting (and controversial) recent developments' in the 'Stanford school of ancient history'and judges Ober's arguments an 'unusually compelling compilation of methods, data and argument in support of a broad thesis.'  Barton Swaim's calls Demopolis: Demcracy Before Liberalism a 'tightly reasoned work of scholarship' in his Wall Street Journal review. 
- Fortress Attica: Defense of the Athenian Land Frontier, 404-322 B.C., Leiden: E.J. Brill, 1985.
- Mass and Elite in Democratic Athens: Rhetoric, Ideology, and the Power of the People, Princeton: Princeton University Press, 1989.
- The Athenian Revolution: Essays on Ancient Greek Democracy and Political Theory, Princeton: Princeton University Press, 1996.
- Political Dissent in Democratic Athens: Intellectual Critics of Popular Rule, Princeton: Princeton University Press, 1998.
- Athenian Legacies: Essays on the Politics of Going on Together, Princeton: Princeton University Press, 2005.
- Democracy and Knowledge: Innovation and Learning in Classical Athens, Princeton: Princeton University Press, 2008.
- The Rise and Fall of Classical Greece, Princeton: Princeton University Press, 2016.
- Demopolis: Democracy Before Liberalism, Cambridge: Cambridge University Press, 2018.
- with Manville, B., A Company of Citizens: What the World's First Democracy Teaches Leaders about Creating Great Organizations, Cambridge, MA: Harvard Business Press, 2003.
- with Eadie, J., The Craft of the Ancient Historian: Essays in Honor of Chester G. Starr, University Press of America: Lanham, 1985.
- with Euben, P., and Wallach, J., Athenian Political Thought and the Reconstruction of American Democracy, Cornell University Press: Ithaca, 1994.
- with Hedrick, C., Demokratia: A Conversation on Democracies, Ancient and Modern, Princeton University Press: Princeton, 1996.
- Described definitively (though not exclusively) by Hansen in his The Athenian Democracy in the Age of Demosthenes: Structure, Principles, and Ideology, University of Oklahoma Press: New York, 1999.
- In his Ancient Democracy and Modern Ideology, Duckworth: London, 2003.
- Peter Rose, 'Secrets of the Ancients', New Left Review 103, January-February 2017
- In The Times Higher Education Supplement.
- InThe American Journal of Philology 121 (2000), 482.
- Roberts, Russ (August 6, 2012). "Ober on the Ancient Greek Economy". EconTalk. Library of Economics and Liberty.
- "Democratic Lessons: What the Greeks Can Teach Us, (Part I) - A Conversation with Josh Ober", Ideas Roadshow, 2015
- "Learning from Athens", 2006
- "Classicists Crunch Data to Test Hypotheses about Greece", 2015