Energy poverty represents a substantial burden on development strategies in the developed and developing world alike, accounts for several hundred thousands excess deaths per year worldwide, and is deeply interconnected to other problems in climate justice and social development. Despite its global relevance and the fact that there has been increased attention to it by governments, academia, and international institutions in the last two decades, the field lacks a clear theoretical foundation, represented mainly by the absence of consistent and agreed-upon conceptual and measurement approaches. This research presents an extensive systematic literature review of energy poverty and related terms since the 1970s and up to the year 2020, focusing on theoretical and methodological contributions. The objective is to synthesize the most influential doctrines, trends, and insights about the phenomenon. The results show that conceptual diversity goes beyond the widely recognized dichotomy between the Global North and Global South, despite several attempts to move towards a composed theoretical framework. Moreover, they also show that measurement, rather than theoretical development, has been the field’s primary focus, leading to many composite and single metrics. Due to the latter, the conceptual development has followed measurement advances instead of epistemological, semantic, or philosophical discussions, though this has started changing in recent years. Finally, considering energy poverty as a broader phenomenon has fueled a more profound debate on justice, which offers a more comprehensive understanding of the actual and expected position of energy poverty in society and development.