The process and salient features of modifying the structure of dielectric nanocrystalline vanadium dioxide films by doping with Ni and W transition metals have been studied. The dielectric spectra obtained experimentally were interpreted in terms of Debye relaxation theory and the equivalent circuits method. The changes in the spectra of doped compounds were established to be due to the selective effect of the dopants on various morphological structures of the film surfaces. It was shown that dielectric spectroscopy made it possible to obtain detailed information about parameters of relaxation response of different-sized morphological structures of films, and such information could not be extracted by other research methods.