The EU humanitarian aid policy constitutes a paradigmatic example of how governmental and non-governmental dimensions interact directly and indirectly. This chapter is a theoretical introduction to the main arguments and is based on International Relations theories, as well as the main interdisciplinary debate. Based on the assumption that, in the current phase of world politics, the global institutions are undergoing a process of change, and that the relations among civil society organisations and institutions in public policy-making need further research, the chapter introduces the literature on the tasks and relevance of NGOs in the humanitarian actions, then discusses the innovative contributions on complex emergencies and transboundary crises, and finally combines diverse literature for postulating a more comprehensive framework that can be used to analyse empirical data and offer some preliminary conclusions.