This study explores the synthesis, structural, and electronic modifications of zinc sulfide (ZnS) thin films doped with tin (Sn) for enhanced functionality in optoelectronic and gas-sensing applications. Utilizing the spray pyrolysis technique, ZnS thin films were doped with varying Sn concentrations (10-25%) to evaluate the influence of Sn on crystallinity and sensitivity properties. Structural and morphological analyses via X-ray diffraction (XRD), FE-SEM and EDX revealed that Sn doping enhances crystallite size and reduces lattice defects, while Fourier-transform infrared (FTIR) spectroscopy confirmed successful incorporation of Sn within the ZnS lattice. Also, gas sensor tests conducted exclusively with 25% Sn-doped ZnS films showed heightened sensitivity and faster response times to H2, suggesting their potential for efficient and durable gas-sensing applications. These findings underscore the suitability of 25% Sn-doped ZnS thin films for advanced sensor and optoelectronic devices. In conclusion, High-performance gas sensor devices with Sn-doped ZnS Thin Films were obtained by optimizing the preparation conditions. Gas-sensing evaluations indicated that Sn-doped ZnS films showed higher sensitivity and faster response times compared to undoped ZnS, making them suitable candidates for responsive and durable gas sensors.