This article argues that corporations and armed opposition groups have obligations under international law. It is suggested that the scope of the obligations turns on the capacity of the entities in question. While there may be no international court to hear complaints against such entities, understanding their legal obligations under international law is important in situations where national courts have jurisdiction over violations of international law committed by non-state actors. Furthermore, it is vital to realizing the potential of claims of corporate complicity in international crimes and the impact such claims may have in the field of ethical investment. [refers to Total, Blackwater]