In the wake of negotiated settlements to civil wars, one critical problem involves reassuring people who have been killing one another that conflict is not about to break out again, endangering people's lives. Those concerned with the success of negotiated settlements have debated how best to enhance the prospects of a stable peace. We address this question by exploring variables that may explain the longevity of negotiated peace settlements. These variables are divided into two categories—one tapping into the potential effects of the environment in which settlements are negotiated and another focusing on the impact of settlement arrangements. On the basis of our analysis of thirty-eight civil war settlements negotiated between 1945 and 1998 we identify the environmental factors and institutional choices that affect the short-term stability of the peace following civil war.