Abstract
The present article reconstructs an often-neglected international political theory: libertarianism. In what follows, libertarianism is presented as a distinct branch of liberal theory, differing from both classical liberalism and, in particular, modern-day IR liberalism. To this end, the pillars of the libertarian outlook on international relations are reviewed: the sharp distinction between the incentive structures shaping the behavior of state and private actors in anarchy, a critique of public goods theory, the notions of decentralization and secession, and libertarian ethics of war. This reconstruction is followed by a juxtaposition of libertarianism with the major IR paradigms, especially liberalism. The article ends with several suggestions for future libertarian research.