The article examines the role of institutions in mediating the interface between global challenges, transnational partnerships and the domestic politics of sustainable development. Empirically it focuses on the Amazon Region Protected Areas (ARPA) partnership, as a new type of governance that engages transnational and domestic actors in pursuing more sustainable management of land use, biodiversity conservation and sustainable development in the Brazilian Amazon. Drawing on extensive documentary analysis and field work, the study analyzes ARPA's institutional and political effects in Brazil. The case study reveals the materialization of a range of capacity-strengthening and environmental impacts, alongside with institutional and distributional effects. ARPA has also built upon the infusion of significant domestic resources and relied on a conductive political environment and pre-existing initiatives. Domestic institutions have thus been arbiters of transnational influence, engaging with the partnership first and foremost to support state and sub-state institutions and ambitious conservation priorities. On the other hand, while local communities and civil society organizations managed, through advocacy pressure and consultations, to incorporate a greater attention to local livelihoods and participation, the socio-economic components of the program remained weaker, with more limited success in terms of poverty alleviation. The conclusion draws broader implications for? the role of transnational partnerships in linking the global governance of environmental systems, domestic institutions and development objectives.