A theory of polar optical vibrations in multilayer semiconductor structures is developed taking into account phonon dispersion. A method of diagonalization of the equations of motion for inertial polarization vectors in the finite basis is used, that is founded on a finite number of degrees of freedom of the system. The Hamiltonian of the electron‐phonon interaction is deduced. The dispersion law and the spatial dependence of the obtained eigenmodes are in good agreement with experimental data and microscopic models. It is shown that the electron scattering rate in a magnetic field depends on the chosen model of polar optical vibrations.