Abstract Cerium oxide thin films are coated on glass substrates by nebulizing spray pyrolysis technique using cerium nitrate and cerium chloride as a source material. Their crystallographic structures, surface morphology, optical properties and I–V characteristics are analyzed as a function of substrate temperature (300–500 °C). XRD is used to estimate the crystallographic texture, crystalline size, strain and lattice constant. All films exhibit a cubic fluorite structure with different preferred orientation depending on the preparation conditions. All the films exhibit dense, smooth and crack-free spherical nanostructures with some uneven surfaces in the range 400 nm. PL analysis indicates the presence of indigo and blue emission in the visible region centered at ∼425 and ∼467 nm respectively. UV-ViS spectra revealed that the films are transparent (70%) in the visible region. Optical parameters like refractive index, optical conductivity and band gap are calculated for different Ts. XPS analysis revealed the existence of Ce, O and C in the films. It demonstrates the prevalent occurrence of Ce4+ rather than Ce3+. I–V characteristics confirm the semiconducting behavior of cerium oxide thin films due to its linear response to applied voltage.