<p>International organizations (IOs) are essential for solving global problems, but the resources that undergird their vitality—money, staff, and support—have come under intense strain. This special issue advances the research program on IO resourcing by addressing three critical gaps. First, contributors provide new fine-grained data to track how states leverage heterogenous resource types to enhance institutional control, moving beyond resource aggregates to analyze the “re-nationalization” of IO activities. Second, the articles highlight under-researched drivers of resourcing, from geopolitical competition and structural geography to the domestic ideological shifts of member states. Third, the issue explores the complex interplay between different types of resources, such as earmarked funding and staffing representation. Collectively, these studies reveal that resourcing is a strategic tool used to navigate and shape a fractured international order. We find that while resourcing can act as a centripetal force for collective action, current patterns increasingly exert centrifugal pressure. By creating “siloes of influence” through earmarked funding, bilateral staffing programs, and partial representational practices, state decisions further entrench the fragmentation of global governance. These dynamics often generate operational inefficiencies and transaction costs that undermine the multilateral character and expert authority of IOs. In conclusion, this special issue offers a roadmap for future research to explore how the governance design of IOs and the rise of non-state actors continue to reshape the resource landscape of contemporary multilateralism.</p>