In this paper, we review mathematical models of the Induced Polarization (IP) of ion-conducting porous media. In the first part we consider the IP phenomenological description based on the classical Debye and Pelton models, and we review the Electrical Double Layer (EDL) theory. We concluded that IP can be represented by an equivalent circuit, which consists of a parallel connection of (i) a resistance and (ii) a serial connection of another resistance and a non-ideal capacitor. We stress that IP can be considered as a “twice coupled” phenomenon in sense of the non-equilibrium thermodynamics, because the initial electric field produces the chemical force, which produces, in turn, a secondary electric field. We also note that the phenomenological models predict a parallel connection of conductive and polarizable elements within the studied porous media. Finally we note that an existence of EDL coating the solid phase is a necessary ingredient for appearance of the Induced Polarization.