Iron-doped tin sulfide (SnS:Fe) nanostructured thin films with doping concentrations of 1 and 3 wt% were successfully synthesized using the spray pyrolysis technique (SPT). X-ray diffraction analysis confirmed the formation of polycrystalline films with an orthorhombic crystal structure and a preferred orientation along the (106) plane. The incorporation of Fe enhanced the crystallinity of the films, as evidenced by an increase in crystallite size from 13.56 nm for the undoped sample to 22.78 nm for the 3% Fe-doped film, accompanied by a reduction in dislocation density and microstrain. Atomic force microscopy (AFM) analysis demonstrated that Fe doping significantly improved the surface morphology of the films, resulting in a more homogeneous surface structure. This improvement was evidenced by a reduction in the average particle size from 87.6 nm to 41.1 nm, accompanied by a decrease in surface roughness. Optical studies showed a decrease in the energy bandgap from 1.72 eV to 1.60 eV with increasing Fe content. Gas sensing measurements toward NO₂ at 110 °C indicated that undoped SnS films exhibited the highest sensitivity, while Fe doping reduced performance.