In the present research, thin films of magnesium doped ZnO were elaborated at a concentration of 0.65 M, which were synthesized using the sol - gel method deposited on quartz substrates of dimensions 11mm x 11mm x 2mm by spin - coating. It was possible to evaluate the influence of the effect of the annealing temperature (400, 500 and 600 ° C) and the molar percentage of the dopant (2, 4, 6 and 8%) on the electrical (conductivity) and morphological properties specifically the grain size. It was found that the thin films of ZnO show the best electrical conductivity doped at 2% Mg and without doping 0% Mg being (8.55 and 8.77) 10-7Ω-1cm-1 respectively at an annealing temperature of 600 ° C and the lowest electrical conductivity is given to a doping of 8% Mg with a value of 1.48 x 10-7Ω-1cm-1 at an annealing temperature of 400° C, thus determining that the Conductivity is inversely prop...