The antimony tri-sulphide (Sb₂S₃) films were prepared by thermal evaporation technique. Four thicknesses (300, 521, 643 and 789 nm) were investigated. X-ray diffraction (XRD) analysis showed the amorphous structure of Sb₂S₃ films. Optical analyses revealed that Sb₂S₃ films exhibited optical energy gap between (1.98–1.16 eV) relaying on the film thickness. The films absorption coefficient was found to be higher than 2 × 10⁴ cm⁻¹(above its related optical energy gap) which makes these films reliable absorbers in photovoltaic applications. Optical constants were analyzed using Swanipole's method. The dark dc conductivity measurements of Sb₂S₃ thin films were conducted in the temperature range 298–503 K. The conduction mechanize was analyzed via Mott's variable -range hopping in three dimensions model. The correlated conductivity mechanize with increasing film thickness changed from extended states to localized states. The results revealed that both optical gap and activation energy decreased as the film thickness enhanced.