<p>Gender inequality remains a persistent challenge worldwide, with regional disparities often masked by national-level statistics. This study addresses this gap by developing a Regional Gender Inequality Index as a general framework for sub-national measurement. To demonstrate its applicability, the index is applied to Türkiye’s 26 NUTS-2 regions as a case study, integrating socio-economic indicators. The analysis is based on the Turkish Statistical Institute’s Household Labor Force Statistics microdata set, which includes 635,159 individual observations (311,453 men and 323,706 women), providing a robust empirical foundation. To construct the index, sub-indicators are weighted using the Best–Worst Method (BWM), while the Weighted Aggregated Sum Product Assessment (WASPAS) method is employed for index aggregation. The findings reveal substantial regional disparities, with western regions exhibit a relatively higher level of gender equality compared to eastern regions. The purpose is not to assert superiority over global indices but to demonstrate a region-scale operationalization of their concepts through BWM–WASPAS, which allows analyses beyond what national averages may reveal. By integrating established multicriteria decision-making techniques with large-scale microdata, this study develops a transparent and replicable framework for measuring gender inequality at the regional level. In doing so, it offers methodological refinement and empirical insights that inform both policy discussions and academic debates.</p>