The purpose of this paper is to identify some challenges and opportunities to the management of shared water resources in Southern Africa and the role external development assistance can play. A common denominator for all Southern African countries is that their water resources are shared, scarce and vulnerable. If the water resources of the region are not managed wisely, water could prove to be a limiting factor for sustainable growth, as well as be a source of distrust between countries. The experience from the field of development cooperation indicates that limited support to joint management initiatives, driven by the countries themselves, has a catalytic effect and assists in building confidence, trust and capacity. It is concluded that the capacity to manage water at the national level needs to be strengthened in order to succeed with international initiatives. Two case studies on the Zambezi and the Pungwe rivers, illustrate the cooperative framework that is emerging on the river basin level facilitated through the support of the Southern Africa Development Community (SADC) .