In 2020, COVID-19 emerged and spread rapidly across the globe. Soon thereafter, the World Health Assembly (WHA) proclaimed the immunisation against COVID-19 a Global Public Good in its Resolution WHA 73.1. What the concept of Global Public Good (GPG) entails, both generally, and, in particular with respect to international law, are far from settled. This article aims to further develop an understanding of this concept and to frame its meaning in the context of immunisation against COVID-19. It argues that while the concept originated in economics, it carries normative value and has implications for different areas of international law. The Resolution concretises a duty to cooperate in the context of immunisation. Furthermore, it requires us to think beyond state borders as well as beyond states’ responsibilities and market mechanisms. This article will explore the repercussions of the normative concept of Global Public Goods within the framework of human rights law, international security law, international economic law, and intellectual property rights. The reference to the concept of Global Public Goods provides an overarching framework in a matter that concerns the international community. Thus, it requires us to develop and provide for international instruments of concrete collective action.