The Economic Community of West African States (ECOWAS) Treaty is a multilateral agreement signed by the member states that made up the Economic Community of West African States. The initial treaty was signed by the Heads of States and Governments of the then 16 member states in 1975 in Lagos, Nigeria. With new developments and mandates for the Community a revised treaty was signed in Cotonou, Benin Republic in July, 1993 by the heads of states and government.

On January 29, 2025, Burkina Faso, Mali and Niger officially withdrew from ECOWAS.