The effect of polar additives is introduced into the theoretical model of charge carrier transport by hopping across disordered rigid polymer matrices. The electrostatic charge carrier–dipole interaction causes a broadening of the energy distribution of transport states which results in a decrease in the charge carrier mobility. The mobility depends on the dipole moment, the molecular dimensions of the additive, and the additive concentration. For geometrically similar additives, the mobility decreases with increasing dipole moment. The theory explains well the observed decrease in the mobility of holes in poly(methyl‐phenylsilylene) with increasing concentration of 1‐(benzamido)‐4‐nitronaphthalene. ©1995 American Institute of Physics.