The aim of this essay is to identify a legal basis for accountability obligations of international organizations (IOs) toward individuals affected by their policies. More specifically, I ask why should, for example, the European Union or the World Trade Organization be accountable to individuals who are not citizens of states parties to those organizations, but nevertheless may be affected by their policies. I explore three traditional foundations for accountability obligations under domestic law as potential grounds for such accountability obligation: the rule of law, human rights, and trusteeship. After rejecting the first two candidates, the essay offers the trusteeship concept as one that can and should serve as the normative bedrock for the emergence of administrative law at the global level. I also argue that this concept is already ingrained in the law that is incumbent upon IOs.