African organization established by the Treaty of Lagos in May 1975 to promote economic trade, cooperation, and self-reliance. The organization seeks to harmonize agricultural policies and to facilitate the free movement of peoples, services, and capital between members. The original 15 members were Benin, Côte d'Ivoire, Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, Togo, and Upper Volta (now Burkina Faso). Cape Verde joined in 1977.

ECOWAS contains four specialized commissions: (1) trading, customs, immigration, and monetary payments; (2) industry, agriculture, and natural resources; (3) transportation, telecommunications, and energy; (4) social and cultural affairs.