The southern Mediterranean region faces one of the most important water crises in the world. The combination of aridity, foreign dependency, climate change, misallocation of the resources and escalating human demand make water supply a primary issue for health, economy and poverty reduction. In this context, institutional reform of the water supply sector is of great interest. Thus, the aim of this study is to examine the water regulatory framework in southern Mediterranean countries and the development of private sector participation in the context of water crisis. The first part of the study presents the scope of private sector participation in water supply and its different forms around the world. An extensive review of 22 empirical tests and 48 case studies on the effect of private sector participation in water services has been conducted. This survey shows that private sector participation, per se, in water supply does not systematically lead to gains in efficiency. Reforming the institutional framework is an essential prerequisite for delegating water services. Afterward, the paper focuses on the southern Mediterranean region. It compares institutional arrangements, recent regulatory reforms and experiences with private sector participation in water infrastructure in Algeria, Egypt, Jordan, Morocco and Tunisia...