Energy is critical to all aspects of human development. This chapter argues that energy is related to sustainable development in three ways: (a) energy as a necessity for meeting basic human needs; (b) energy as a source of environmental stress; and (c) energy as a key driver of macroeconomic growth. These three dimensions correspond to the sustainable development tripod: environmental, economic, and social. The chapter discusses how international law deals with the challenges of energy access in sustainable development and how it ultimately guides decision-making in energy investments. The basic goals of international energy policy are well suited to delivering sustainable energy outcomes but this requires articulating and deploying a legal framework that can guide disparate energy investments and innovations along a sustainable pathway. An overarching theme that emerges is that a robust framework on energy for development must have, at its centre, a human rights and sustainable development focus.