The free rider problem is a concept that has primarily been studied in economics. It has also been examined to make sense of the behavior of states in international relations, particularly the small ones. Free riding in international relations is a strategy that small states can adopt. At times, free riding is also an accusation made by large states against small states. The free rider problem is very important, as it concerns the reasons states decide to join an alliance and how they actually behave within an alliance. This entry provides an overview of the free rider problem by looking at what it is and what its consequences are. It then uses the example of the North Atlantic Treaty Organization (NATO) to exemplify it and ...