This research seeks to explain the obstacles to the implementation of peace settlements and to the consolidation of more co-operative and stable political systems in the aftermath of civil conflicts. Peace processes are explored through comparative observation and the theoretical modelling of strategic interactions in the immediate post-settlement implementation process. The study develops the argument that in the factionalism that characterises parties to a civil conflict, and in the multiple motivations that drive individual and group members to support these factions, he the explanations for successful, stalled or unravelled implementation processes. It further considers the proposal that the design of the implementation process, and the political economy at the regional and international level, will have a determining effect on the outcome of implementation to the extent that they impact on the intra-party struggle between factions In developing this argument a new model of implementation - the ‘mtraformation factionalism' or IFF model - is proposed The plausibility of the ‘mtraformation factionalism5 model and its predictions on the design of the implementation process are empirically explored by the application of a number of hypotheses to a dataset of 25 post-settlement civil conflicts This is supported by a further analysis of three in-depth case studies in which the institutional procedures that appear to facilitate the successful implementation of negotiated peace settlements are highlighted.