This chapter describes the use of periodic homogenization technique as a tool for a multiscale homogenization of ionic transfer in cementitious materials. The first homogenization procedure of the Nernst–Planck–Poisson (NPP) system is performed from the nanoscale (Debye length scale) to the microscale (capillary porosity scale), accounting for the electrical double layer (EDL) effects. The second homogenization step is performed from the microscale to the material scale. Accounting for the large volume of cementitious materials usually used in concrete structures, the calculus of transfer properties accounting for all the heterogeneities at the microscopic scale is not conceivable. Therefore, cementitious materials need to be modeled as continuum media with equivalent macroscopic transfer properties. The chapter focuses on the calculation of the homogenized diffusion tensor at the macroscopic scale, accounting for the mutliscale nature of the cementitious material considered.