​Using a realist approach, this study explains the development of international institutions in the Arab system, taking the Arab League and the Arab Monetary Fund as case studies. It puts to the test realist assumptions regarding states as major actors in the international system and examines how the principle of chaos and the absence of central authority affect their behaviour. In this context, the prisoner's dilemma is used as a mirror for security interactions and chaotic structures in the Arab and international systems. The study shows that realist assumptions are not sufficient to explain the development of Arab institutions; they need to be modified to explain the variation in international behaviour in the region. The conclusions of the paper are based on an analysis of the reward environment in which Arab countries interact, and its division into a security-military sphere and a political-economic sphere.