The thin layers of undoped ZnS and ZnS doped La with different concentrations (2, 4, 6, 8 and 10%) were deposited on glass substrates using sol-gel and dip-coating methods. The structural characterization of these samples was carried out by the X-rays diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). UV-visible and Fourier Transform Infrared spectroscopy (FTIR) have been used to study the effect of dopant on the optical properties of ZnS doped La thin films. Atomic force microscopy images of the films have revealed homogeneous and granular structure and the SEM micrographies show deposit films with uniform and porous structure. The optical transmission spectra in the UV - visible range have shown that all the doped films present a good optical transmission in the visible domain.