With the exception of most island nations, every country on the globe is hydrologically connected to its neighbors. This is especially evident in the more than 600 cross-border aquifers that have been identified world-wide and that are being exploited to varying degrees. Surprisingly, and in contrast to the more than 3,600 treaties and agreements governing transboundary rivers and lakes, there are currently only five treaties and a small handful of informal arrangements in place for transboundary groundwater resources. This presentation will provide an overview of the governance of groundwater resources in an international context. It will also address the role that science and policy have in supporting the further development of such regimes, and the role that the International Water Resources Association has taken in bridging the science-policy interface.