Thin films of tin sulphide (SnS) were prepared on glass substrates using the thermal evaporation method and the optical dispersion parameters investigated. The results obtained on the dispersion parameters and other optical constants indicated a strong thickness dependency. The results indicated that the refractive index data obeyed the single oscillator model. The dispersion energy (Ed), optical spectra moments (M-1) and (M-3) and the dielectric constant (ɛ) were all found to decrease with increase of film thicknesses. However, the oscillator energy (Eo) and angular frequency (ωp) are independent of film thickness. These results are useful tool for further understanding the electronic structure for this novel material.