A major issue affecting groundwater management is the lack of communication between the various stakeholders, e.g. the hydrogeologists, the lawyers, the sociologists and the policy-makers. This issue is further complicated when groundwater is transboundary, because of different political priorities, different languages and cultures often leading to different approaches of the same issue, different laws and regulations. The considerable number of transboundary aquifers, either across international boundaries between countries or local boundaries between regions of the same country, implies that this kind of groundwater is becoming a major resource for many countries and its management a major issue. At the political level, it is necessary to have a good understanding of the scientific and technical aspects of transboundary groundwater to take part in negotiations, to make political and managerial decisions, and to create the institutions and instruments necessary for transboundary management, especially joint institutions and partnerships.