Size and system are basic theoretical approaches to the study of the vulnerability of small states. Small size, which is a shared attribute of all small states, is the source of its vulnerability. Nevertheless, small states’ vulnerability and the associated dependence and marginalization are not a constant, because the international system and global discourse have a constitutive impact upon the degree, content and politico-economic significance of its vulnerability. The political significance of size depends on the nature of international political system, while its economic significance hinges upon international economic arrangements. In the context of today’s discourse on international relations, small states’ vulnerability has been mitigated due to the changed systemic nature; moreover, the evolution of globalization has provided small states with a potential turning point. But all these changes do not amount to the elimination of vulnerability for small states: “smallness” still has political and economic significance. Simply put, size has shaped national attributes, and “smallness” and the change of international system have together constituted the nature and content of small states’ vulnerability.