Freshwater is one of the most valuable natural resources on Earth. However, many of the more easily accessible freshwater resources at local and regional levels have suffered from overexploitation due to increasing population density, economic activity, and unsustainable water management practices. Sustainable management of domestic water resources is a challenging task mainly due to water allocation, pollution, and other problems on international rivers. Social science research has contributed in a variety of ways to identifying sources of international conflict and cooperation, water management options, and institutional solutions for achieving sustainable international water management. The scholarly literature has tackled a wide range of crucial questions arising from the politics of international freshwater resources, such as: whether there is sufficient evidence for the “water wars” claim—that is, whether water-related factors influence the probability of armed conflict; the determinants of international river basin cooperation, in terms of policy output and policy outcome or impact; how we can determine whether international water management efforts are successful in terms of solving problems that motivate cooperation; and the extent to which the literature offer insights into institutional design options that are effective in terms of problem solving. These studies have produced a considerable amount of policy-relevant analytical concepts and empirical findings. For example, fairness (equity) is one of the key concerns of all governments when they engage in international water cooperation, and integrated water resources management may look nice on paper but does usually not produce the desired results.