Why do bureaucrats from developing countries cooperate internationally? I argue that international inter-agency cooperation in the Global South results from the need of expert bureaucrats to invest in skill formation when governments do not. When states cut funding, expert bureaucrats cooperate with foreign peers to upgrade their skillsets because career advancement is contingent on up-to-date expertise. To test my theory, I use cross-national co-sponsorship data of projects in nuclear energy, science and technology (NEST) for 69 countries (1980-2008). Results show that bureaucrats cooperate internationally when government spending decreases and that cooperation is more likely to occur among bureaucrats with higher initial skill levels and similar levels of professional development (i.e. homophily). These findings carry implications for the study of global governance in the developing world.