Supranationalism is a method of decision-making in international organizations, where power is held by independent appointed officials or by representatives elected by the legislatures or people of the member states. Member-state governments still have power, but they must share this power with other actors. Furthermore, decisions are made by majority votes, hence it is possible for a member-state to be forced by the other member-states to implement a decision against its will.

An alternative method of decision-making in international organizations is intergovernmentalism.

Few international organisations today operate on the basis of supranationalism; the main exception is the European Union, which incorporates both intergovernmental and supranational elements.