In order to avoid dangerous climate change and to satisfy the global energy needs energy systems have to change. Hopes are especially high in countries of the Global South for the low-carbon transition to propel sustainable development. Yet, while the energy transition provides opportunities, it also raises questions on how to avoid new global inequalities. This study presents the first quantitative approach to measure the extent to which the energy transitions in the Global South incorporate elements of energy justice. In doing so, this study builds on a rich literature on energy justice that differentiates between distributional, recognition, and procedural justice, thus taking into account social and development objectives such as affordability and accessibility of energy, the inclusion of marginalised parts of society, as well as broader community involvement and participation. Though much important conceptual and qualitative work has been done, what has been lacking so far is a quantitative measure of the degree to which the energy transition lives up to the imperative of energy justice, going beyond the much-studied Global North. The proposed energy justice index is designed and applied to select countries from Southeast Asia (Malaysia), sub-Saharan Africa (Kenya), the MENA region (Jordan), and Latin America (Chile). The index stands the test of the empirical application and demonstrates significant variation between countries along the different dimensions of energy justice. The study also emphasizes the importance of further testing and of improving data quality for informed policy making of energy justice issues in the Global South.