<p>Countries differ in their energy infrastructures, economic structures, and socioeconomic contexts, resulting in uneven vulnerability to the energy transition. Advancing a just global transition requires that the most vulnerable are not left behind and that all countries make measurable progress. To support this effort, we introduce the Energy Transition Vulnerability Index (ETVI), a global metric assessing national-level vulnerability. The framework draws on the Vulnerability Scoping Diagram and evaluates vulnerability across three dimensions—exposure, sensitivity, and adaptive capacity—in accordance with the Intergovernmental Panel on Climate Change (IPCC) definition. The dataset provides ETVI scores and sub-indices for 142 countries and regions from 2000 to 2023. Developed using a consistent methodology, the spatiotemporal dataset supports both cross-country comparison and within-country tracking over time, and serves as a foundation for further research. Insights derived from such research can inform the design of inclusive energy transition strategies and support international policy coordination.</p>