How and why do some civil wars end in a peace that endures while other civil wars re-ignite? The existing literature comes to contradictory and puzzling conclusions. For example, while some scholars and development practitioners argue that differences in post-conflict peace-building outcomes were to be explained by the intervention of the international community, other scholars focus on how a civil war ends -whether it ended in a government victory, a rebel victory or a negotiated settlement. By contrast, more recent studies find that states' attributes such as the level of economic development; pre-war level of democracy; the degree of ethnic fractionalisation; and state dependence on oil exports influence the outcomes of post-conflict peacebuilding. Although these explanations focus on different aspects and use different explanatory variables to explain the variation in post-conflict peacebuilding, they are complementary and overlapping in many important ways. This paper presents an in-depth review of a wide body of theoretical and empirical research on post-conflict peacebuilding. The review covers three stands of literature on peace and conflict research which include: (1) those that focus on the root causes of the initial conflict, (2) those that focus on how the original war was fought, and finally, (3) those that focus on post-conflict peacebuilding. The insights from this literature reveals that while existing studies on the transition from civil war to peace have yielded considerable insights, there are a number of weaknesses and gaps. Some policy conclusions are drawn and directions for future research are suggested.