This document summarizes a presentation given at the GEF International Waters Science Conference in 2012 on the role of science in transboundary aquifer management. The presentation discusses how aquifers function as underground reservoirs that store and transmit groundwater. It also notes that the availability and quality of groundwater is largely dependent on geology. Several major transboundary aquifer systems, including the Guarani Aquifer in Latin America, are mentioned. The presentation identifies ways that science has helped provide understanding of groundwater occurrence but also notes limitations like poor communication of results. It concludes that science can enhance knowledge of aquifer systems and help fill gaps between research and application to support holistic groundwater management.