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.