The Economic Community of Western African States (ECOWAS) offers a large and diverse market of over 400 million people and natural resource wealth, and yet it is not currently living up to its potential as a destination for international investment. Inflows of foreign direct investment (FDI) in the region have been declining over time, and have not always delivered on promoting sustainable development. This report serves as a baseline diagnostic to explore ways to reinvigorate the reform of the ECOWAS investment climate while also improving sustainable outcomes from investment. It also highlights areas where further collaboration between ECOWAS and the OECD could contribute to improved investment climates throughout the region. Building upon the OECD Policy Framework for Investment and the FDI Qualities Policy Toolkit, the report covers the national regulatory framework encapsulated in national investment laws and how this compares with initiatives at a regional level, investment promotion and facilitation, investment incentives, investment for green growth and responsible business conduct.