North Africa and the Middle East have the largest solar energy potential in the world (World Bank 2010). Developing solar energy is capital intensive, and the Mediterranean region is not rich in private and public capitals. This means that the transition to solar energy has high initial costs that Mediterranean countries cannot afford alone. Experts and political scientists have been working on how to scale-up solar energy investment to targeted countries (scaling-up problem). However, official reports showed that the shift to solar energy is taking place in very few Mediterranean countries rather than within the region as a whole (UNEP 2012). Surprisingly, no specific attention is being devoted to the problem of ‘how a region-wide transition to solar energy can be achieved in the Mediterranean’ (widening problem). The TRANSOLAR project is tackling the ‘widening problem’ directly on the ground. Drawing on comparative country-case studies in five selected countries (Morocco, Algeria, Tunisia, Egypt and Turkey) between 1994 and 2012, This project will offer an in-depth study of: (a) the regulatory frameworks and existing financing mechanisms in the Mediterranean region; (b) the limits and potential of Euro-Med renewable energy cooperation; (c) and the state of public participation (i.e. civil society at large) and transfer of know-how in the field of solar energy within the Mediterranean region. To gather evidence, this project will employ the following methods: semi-structured interviews with policy makers, questionnaires and a participatory assessment with public/private decision-makers. As a result of this, this project will build knowledge on how to facilitate a region-wide transition to solar energy in the Mediterranean. KEYWORDS: Socio-Technical Transitions in Developing Countries, Solar Energy, Euro-Med Relations, Governance Studies, International Relations.