The study of international organizations’ (IOs) peer review systems has focused largely on their efficacy in disseminating best practices, with mixed results. This paper informs the debate from a new angle: We evaluate the extent to which decisions about who reviews whom and where result from bureaucratic guidelines, or whether these decisions are shaped by the particularistic interests of member states that would need to be considered in efficacy evaluations of peer reviews. Our empirical case is the OECD Development Assistance Committee (DAC) which requires that DAC donors have their practices reviewed by two peer examiners every few years. Using quantitative and qualitative methods, we study (i) the assignment of peer examiners (1962–2020) and (ii) the selection of recipient countries visited for in-depth assessment during the review (1994–2020). Our analyses show that the choice of peer examiners is driven by the IO’s bureaucratic process. The selection of recipient countries for field visits is also largely in line with Secretariat guidelines, with some room for the preferences of reviewed donors to play a role.