Today 65,3 million people were obliged to flee their homes to avoid the consequences of armed conflicts, generalized violence and massive human rights violations, thus creating the worst forced displacement crisis since World War II. While 24,5 million people crossed international borders to seek refuge in other countries, the majority of people, 40,8 million, remained within the limits of their countries of residence, in places closer to conflict zones and in situations of extreme vulnerability. This category of people, called "internally displaced persons" (IDPs), was not granted with international treaties and institutions for their protection in the 1950s, as was the case with refugees. On the contrary, IDPs had to wait until the end of the 1990s for the development of the first normative and institutional arrangements that recognized their human rights and that prescribed protection responsibilities to States and to international organizations. This thesis seeks to uncover the elements and processes, at structural, agentic and interactive levels, that account for the emergence of the international norm of IDP protection. It also explains what kind of protection is foreseen by the norm and how it was discussed and constructed through time. Through the analysis of six decades of the history and geopolitics of global forced displacement, the thesis argues that the protection of IDPs went through four main phases during its process of norm emergence: (i) the identification of the issue as being internationally relevant in the 1970s; (ii) the moral problematization of the absence of consistent IDP protection in the 1980s; (iii) the dispute between two different norm proposals in the 1990s, one based on human rights regimes and the other, on pragmatic protocols of humanitarian action; and (iv) the accommodation between the two normative proposals and the following consolidation of a hybrid international norm, located between human rights and pragmatic humanitarianism.