Assessing groundwater vulnerability to anthropogenic contamination is essential in protecting and sustainably managing these valuable resources, particularly in arid and semi-arid regions. This study was performed in the alluvial aquifer of the Hennaya Plain (North-West Algeria) to evaluate aquifer vulnerability using a comparative analysis of GIS-based DRASTIC, SINTACS Intrinsic Vulnerability Index (SIVI), and SINTACS Specific Vulnerability Index (SSVI) models. This multimethod approach aimed to determine the most reliable model for this area. The spatial distribution of the vulnerability index in all models showed tendencies toward moderate, high, and very high vulnerability. These results demonstrated that the middle and northern parts of the plain displayed heightened susceptibility potential, whereas the southern part exhibited the lowest susceptibility potential. Furthermore, Nitrate (NO3-) concentrations from groundwater samples were utilized to validate the vulnerability models. The findings indicated that the DRASTIC and SSVI methods were the most accurate, with the SIVI model following in accuracy. Finally, map removal sensitivity and single-parameter sensitivity analyses demonstrated that aquifer medium and soil type were the least influential factors for the DRASTIC and SSVI susceptibility indices, whereas depth to the water table, vadose zone, and land use were the most critical. The conclusions of the current study, derived from a pilot investigation carried out in the Hennaya Plain, offer significant insights that contribute to the improved understanding and management of precious groundwater resources.