Sn-doped In2S3 thin films are deposited on Pyrex. Tin is incorporated in the solution using SnCl2 center dot 2H(2)O. The properties of the films are investigated by X-ray diffraction (XRD), atomic force microscopy, scanning electron microscopy, spectrophotometry, and thermally stimulated current (TSC) measurements. XRD analysis reveals that the films become almost amorphous when tin exceeds well determined optimum quantity. The investigation of optical properties shows that the band gap depends on the value of the Sn concentration. It is also observed that upon adding the optimum quantity of tin, the maximum of the TSC intensity increased by 2 orders of magnitude. These results are discussed with respect to introduce the effect of tin incorporated in the physical properties.