This report has three objectives: Firstly, it illustrates how SEAs can be applied in development co-operation by presenting nine detailed case studies. Secondly, it reviews the outcome of these nine SEAs by examining how the SEA process changed original policies, plans and programmes. Finally, it concludes with lessons that can be learned from these case studies, for future practice. It reviews strategic environmental assessment experiences in development co-operation in the following developing countries: Benin, Bhutan, Ghana, Honduras, Mauritius, Montenegro, Namibia, Sierra Leone and Vietnam. In 2006, a task team of experts from development agencies in the Development Assistance Committee (DAC) drafted the SEA guidance document “Applying Strategic Environmental Assessment: Good Practice Guidance for Development Co-operation”. The introductory chapter of this report provides contextual background on the situation before the SEA Good Practice Guidance was published. It contains some of the rationale behind the publication of the SEA guidance, and concludes with an overview of the structure followed in this review.