Renewable energy sources (RES) have significant potential to contribute to the economic, social and environmental energy sustainability of small islands. They improve access to energy for most of the population, they also reduce emissions of local and global pollutants and they may create local socioeconomic development opportunities. The aim of this paper is to provide a review of the theoretical and empirical literature on the contribution of RES to the energy sustainability of islands, focusing on the main results and the methodologies used. Papers are classified according to their coverage of the three dimensions of the triangular approach to sustainability (economic, environmental and social). The review also takes into account whether and how the procedural sustainability has been tackled in those papers. It is acknowledged that although several topics have been covered by the existing literature, there are promising avenues for future research on several fronts, both thematic and methodological.