Hydrological drought is a critical factor affecting ecosystems and water availability in semi-arid regions. This study evaluates hydrological drought conditions in the Greater Zab watershed using the Drought Vulnerability Index (DVI). The methodology integrates geographic information system (GIS) and remote sensing techniques with a multi-criteria decision analysis (MCDA) approach. Specifically, the analytic hierarchy process (AHP) is employed within the DVI framework to evaluate the spatial distribution of hydrological drought vulnerability across the watershed. The analysis incorporates various hydrological, topographical, and environmental criteria, including temperature, precipitation, solar irradiation, slope, the Normalized Difference Water Index (NDWI), the Topographic Wetness Index (TWI), land cover, soil types, and stream networks. These criteria were selected due to their significant influence on hydrological drought conditions. The results indicate that 55.7% of the watershed exhibits low to moderate vulnerability to hydrological drought. Conversely, 15.5% of the area exhibits very low vulnerability, indicating regions minimally affected by hydrological drought hazards. However, the southern portion of the watershed displays a higher susceptibility to hydrological drought, with 28.8% of the area classified as experiencing high to very high levels of hydrological drought. These zones are particularly vulnerable due to the combined effects of climate change, distinctive topographical features, increasing temperatures, and decreasing precipitation.