This paper examines the institutional mechanisms supporting the ethical oversight of human participant research conducted by the United Nations (UN). The UN has served an instrumental role in shaping international standards on research ethics, which invariably require ethical oversight of all research studies with human participants. The authors’ experiences of conducting research collaboratively with UN agencies, in contrast, have led to concern that the UN frequently sponsors, or participates in, studies with human participants that have not received appropriate ethical oversight. (...) It is argued that the institutional mechanisms in place to prevent research with human participants from being undertaken by the UN without ethical oversight do not, at present, extend substantively beyond the provision of guidelines and online training offered by a minority of UN bodies. The WHO and UNICEF are identified as notable exceptions, having implemented various measures to prevent health research with human participants from being undertaken without ethical oversight. Yet, it is highlighted that the WHO and UNICEF are not the only UN bodies that undertake health research with human participants and there are countless actors under the umbrella of the UN system that are regularly involved in non-health research with human participants. Arguments for the pursuit of the highest standard of ethical oversight by UN bodies are presented. Moving forward, the paper asks the question: is it time for the UN to set the standards for the oversight of ethical oversight? (shrink)