A low-cost and up-scalable fabrication method for high-quality gallium oxide films using spray pyrolysis from water-based solutions and moderate temperatures is presented. The solution chemistry and spraying process parameters were optimized to obtain homogeneous films on glass and three different transparent conducting oxide substrates. Structural and optical film properties of the deposited nanocrystalline Ga2O3 were evaluated by scanning electron microscopy, grazing-incidence X-ray diffraction, atomic force microscopy and optical spectroscopy. The elemental composition of the surface and the bulk film was analyzed by X-ray photoemission spectroscopy depth profiling. To show the applicability of the deposited Ga2O3 in electronic devices, the electronic valence region of the material was studied by ultraviolet photoemission spectroscopy, resulting in an energy level diagram of the material.