In a seminal article, Stedman (International Security, 22, 1997, 5) suggested that the greatest source of risk to civil war peace processes comes from so-called spoilers, leaders, and groups that perceive peace as threatening and use violence to undermine attempts to achieve it. The spoiler concept has since gained significant ground and widespread legitimacy both in the academic literature and in critical policy circles. In the footsteps of this development, however, we suggest that the spoiler concept has been stretched beyond its original meaning and given raise to a number of ambiguities concerning its definition and empirical applicability. This lack of clarity in regard to some of the key aspects of the spoiler concept does not only risk undermining the usefulness of the concept itself, but also risks hampering the accumulation of valuable research on this pertinent topic. This article presents a reflection on a burgeoning research field and aims to contribute to the same by attempting to offer greater conceptual clarity in regard to a number of issues that are the core of the spoiler debate and by presenting a conceptual framework for analyzing spoilers in future research.From ongoing peace efforts around the world-in Colombia, the Democratic Republic of Congo, Israel and Palestine, Nepal, the Philippines, or Sudan-we receive almost daily accounts of broken peace talks, interrupted disarmament efforts, violent incidents, and political assassinations that speak to the importance of better understanding the patterns and processes of peacemaking in civil wars. In a seminal article, Stedman (1997) suggested that the greatest source of risk to peace processes comes from so-called spoilers: leaders and groups that perceive peace as threatening and use violence to undermine attempts to achieve it. Although Stedman was not the first to identify the problem or the first to address it, the article was a novel attempt to develop a typology for categorizing different actor types based on their motives and means of spoiling, and discuss the policy implications of various third-party strategies for managing such actors in internationally supervised peace processes. Since then, the concept of spoilers has been frequently referred to and gained widespread usage and legitimacy 1 We would like to thank Thomas Ohlson and the Research Article Seminar at the Department of Peace and Conflict Research, Uppsala University, for many useful suggestions. A previous version of this paper was also presented at the National Conference on Peace and Conflict Research, Uppsala, December 16-17, 2010, and we would like to thank the participants for valuable discussions. We also wish to thank the three anonymous reviewers for their constructive comments on an earlier draft, from which the final version has greatly benefited. We gratefully acknowledge financial support from the Swedish International Development Cooperation Agency (Sida), Riksbankens Jubileumsfond, and the SYLFF Endowment at Uppsala University.