This paper presents the results of investigation of aluminum-doped zinc oxide thin films obtained by radio-frequency magnetron deposition on a glass substrate. It was shown by energy dispersion X-ray spectroscopy that the average aluminum content in the thin films was 0.2–0.8 at.%. An increase in the average grain size with increasing aluminum concentration was shown, and column-like growth of the films was established using microscopic images. Investigation of the electronic structure showed a redistribution of intensity in the O 1s spectrum with aluminum doping. The valence band spectra were also obtained, and theoretical calculations were performed within the framework of density functional theory to better understanding the results. Using a spectrophotometer, the transparency of the films obtained after aluminum doping was shown to increase. With the help of the Tauc method, the band gap was determined to be 3.41 eV, while DFT calculations showed a band gap of 1.25 eV.