In political ecology, violence is usually associated with conflicts over the control of natural resources. Up to now, political ecology has lacked a sound conceptual approach for analysing how violence that has its origin in political conflict induces environmental and social change. This article examines how the environment serves as an arena for exerting power, by using different forms of violence, affecting both ecosystems and the entitlements of the people who are dependent on natural resources. After a brief description of the role of violence in political ecology research, a conceptual framework for a political ecology of violence is laid out. In this framework, the notion of ‘violent environments’ introduced by Nancy Peluso and Michael Watts is blended with new approaches in livelihood research in which the political dimension of livelihood processes is emphasized. Case study material from eastern Sri Lanka, an area affected by prolonged violence and protracted conflict, is presented. This illustrates how violent struggles over environmental entitlements and the politicization of resource-based livelihoods created alternative systems of power and control over natural resources and triggered new processes of disentitlement and social vulnerability.