This article examines the role of development co-operation in the 1991-2001 civil war in Sierra Leone. British military intervention, sanctions against Liberia for supporting the rebellion and the deployment of UN peacekeepers were key, albeit belated, initiatives that helped resolve the conflict. The lessons are that, first, domestic forces alone may be incapable of resolving large-scale violent conflicts in Africa. Second, conflict tends to spread from one country to another, calling for strong regional conflict resolution mechanisms and deeper regional integration to promote peace. Third, donor policies need to address the root causes of state fragility, especially the political and security dimensions, which they tend to ignore. Fourth, a critical analysis is required to determine circumstances in which elections could undermine peace: the conduct of donor-supported elections under an unpopular military government in Sierra Leone culminated in an escalation of the conflict. Finally, a united international community is crucial to resolve a complex conflict and it should be accompanied by strong and timely measures informed by a full understanding of local conditions.