A unified extension of the classic Shilov-Dukhin theory of the low frequency dielectric dispersion of colloidal dispersions is presented. Purely analytical expressions for the AC dielectric and electrokinetic response over a broad frequency range including different counterion and co-ion valences and the presence of the stagnant layer conductivity are deduced The obtained results are generally in good to very good agreement with available numerical data, showing that they should be useful for the interpretation of a broad range of experimental results without having to rely on numerical calculations.