This chapter examines the neoliberalist argument that international institutions promote international cooperation. While neoliberalism acknowledges that cooperation can be difficult to achieve in anarchic conditions, it insists that institutions allow states to overcome a variety of collective action impediments. The central concern of neoliberal analysis is how institutions do so, and how they might be redesigned to more efficiently obtain cooperative outcomes. This chapter considers three questions that are relevant for understanding neoliberal contributions: How did neoliberalism emerge? What are the barriers to international cooperation? How does neoliberalism study international institutions? The chapter uses the World Trade Organization as a case study to illustrate the importance of institutional design for international free trade cooperation. Along the way, various concepts such as interdependence, hegemonic stability, hegemon, bargaining, defection, compliance, autonomy, and principal–agent theory are discussed, along with the game known as Prisoner’s Dilemma.