Non-Governmental Organisations (NGOs) use the United Nations human rights system to hold governments to account. Drawing on international interviews and an Australian case study, this article compares the NGO role in two UN human rights state reporting mechanisms—that of the treaty bodies, and the Human Rights Council’s Universal Periodic Review (UPR). It finds that treaty bodies are more accessible, providing NGOs with more opportunities to have their voices heard and to influence recommendations. Through this analysis of the NGO role, complementarity of the mechanisms is also considered, including the risk that the UPR could colonise treaty body state reporting.