It is abundantly clear that adequate, reliable and clean energy services are vital for the achievement of many of the Sustainable Development Goals (SDGs). In essence, energy access has come to represent one of the intractable challenges in development, and therefore emblematic of the call for poverty eradication, and economic and social transformation. This focus issue on “Energy Access for Sustainable Development” is initiated to draw broadly from the ideas and emerging experiences with energy activities and solutions that sought to enhance sustainable development through expansion of energy access. The focus issue includes several contributions from authors on some of the knowledge gaps this field, including: (i) the role of off-grid and mini-grid energy systems to meet multiple SDGs; (ii) the impacts of the evolving suite of off-grid and distributed energy services on inequalities across gender, and on minority and disadvantaged communities; (iii) the opportunities that the evolving technology base (both of energy services and information systems) plays in expanding the role of off-grid and mini-grid energy systems; (iv) energy options for cooking; (v) new insights into energy planning as well as the political economy, institutional and decision challenges across the energy system. Drawing from papers in this focus issue and other literature, this paper provides a sketch of the key issues in energy access.