The Brahmaputra River is one of the world’s largest transboundary waterways, yet it lacks a coherent, international management framework. The river, which flows from China through India and into Bangladesh, has been subject to decades of stalled negotiations, gamesmanship, and stop-gap oversight measures. As climate change and population growth place new stressors on the Brahmaputra and its riparian states, this arrangement will become untenable. Moreover, obtaining consensus may soon become impossible as the region grows increasingly water scarce. There is a brief window of opportunity to rectify inadequate management of the river and address urgent issues such as environmental protection and apportionment of the water’s resources. The recent opening of the UNECE Water Convention to non-European signatories provides a mechanism to do so: The Convention’s adherence to common international law water principles, its incremental approach to collaboration, and its focus on environmental stewardship and scientific data sharing provide an ideal model to initiate multilateral cooperation between the Brahmaputra riparian states. Strong multilateral foundations should be established before the region is confronted by a changing physical landscape caused by climate change; the UNECE Water Convention provides such a structure and should be utilized.