Tungsten trioxide (WO3) thin films were deposited by thermal evaporation technique and annealed at 623 K for 1 h. The influence of lithiation on the optical properties of the deposited films was studied. WO3 films exhibit a high optical transmittance and reduced by increasing the amount of injected lithium. The optical band gap was calculated for all the samples and it changes from 4.5 to 4 eV. The electrical conductivity of different lithiated WO3 crystalized films was studied depending on temperature. The resistance behavior follows the Drude Model. This model has been verified for different amounts of lithium x. The validity of Drude model for the temperature range from 273 to 333 K is fulfilled. The activation energy as well as the optical bad gap decrease as the amount of Li changes from 0.03 to 0.5. The carrier concentration as well studied.