Scant attention has been paid to how field presence shapes the implementation of environment-earmarked projects by international organizations (IOs), such as those funded by the Global Environment Facility (GEF). GEF funding is based on a process whereby implementing IOs and recipient partners co-design projects based on GEF criteria. Once approved by GEF, projects are implemented with no direct GEF involvement, but are later evaluated by a dedicated GEF unit. We assume that IO country officials are key players in project implementation processes, and we expect that their field presence shapes implementation performance. Drawing on data from approximately 1,000 GEF projects delivered by five implementing IOs from 1997 to 2020, our analysis suggests that implementation performance is evaluated better where IO country officials have greater field presence. This has implications for debates on multilateral funding, IO bureaucracies, localization, and IO performance.