Five types of nanostructured films produced by a sol-gel method were investigated to enhance the electrochemical, optical, and mechanical properties of electrochromic tungsten oxide films. WO3 films containing SiO2 and TiO2 nanoparticles offered promising results of high coloration density and fast response time. The film based on WO3-x-0.1TiO(2-y) sol-gel solution mixed with oxalic acid was found to be stable and has excellent characteristics in coloring/bleaching kinetics.