<p>This study aimed to develop a regionally adapted composite index to measure vulnerability in energy poverty across Indonesia’s provinces and to analyze spatial disparities using a multidimensional vulnerability framework. The central research question was: <i>How can geographic</i>,<i> socio-economic</i>,<i> and institutional characteristics be integrated into a composite index to identify and systematically compare regional vulnerability in energy poverty across Indonesia?</i> The Regional Vulnerability to Energy Poverty Index (RVEPI) integrated 15 indicators across three Intergovernmental Panels on Climate Change (IPCC)-based dimensions: exposure, sensitivity, and adaptive capacity. Unlike previous indices, RVEPI included context-specific variables such as the island-to-land area ratio and multi-hazard risk to capture the geographic fragmentation and disaster vulnerability unique to archipelagic nations. The study was guided by the hypothesis that <i>regions with high exposure and sensitivity and low adaptive capacity will exhibit the highest energy poverty levels</i>. The RVEPI was constructed using both dimension-weighted and variable-weighted aggregation schemes. Validation through Spearman’s rank correlation (ρ = 0.99) and mean absolute deviation confirmed the index’s robustness. K-means clustering revealed three typologies of regional vulnerability: severe multidimensional, moderate structural, and low vulnerability with strong adaptive capacity. Findings highlighted a persistent east–west divide, with provinces in Eastern Indonesia, such as Papua, Maluku, and East Nusa Tenggara, ranking highest in vulnerability due to remoteness, limited infrastructure, and weak governance capacity. The RVEPI offers a spatially sensitive, policy-relevant diagnostic tool to inform equitable energy planning in fragmented geographies. It also supports the just implementation of Sustainable Development Goal 7 (SDG 7) in Indonesia and provides a replicable framework for other island nations facing similar challenges </p>