Obstacles to transboundary water cooperation in the Ganges–Brahmaputra problemshed are discussed in this chapter. There is underdeveloped civil society and weak regionalism. At the same time, South Asian states see collective action as a threat to sovereignty. As such, zero-sum attitudes to water sharing prevail, and transboundary water issues are securitised. A culture of secrecy prevails around hydrological data, and this impedes trust and cooperation between riparian states. All these factors make the work of third parties more challenging – and all the more important.