The Bi2O3 thin films were prepared onto glass substrates by spray pyrolysis method. The Bi2O3 thin films optimized at 320 °C spray pyrolysis temperature. The crystal structure, crystallite size, and surface morphology of Bi2O3 thin films were studied by X‐ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The X‐ray diffraction pattern of Bi2O3 thin films show polycrystalline in nature. The SEM images show porous morphology of Bi2O3 thin films. The optical absorption spectra of films were examined in order to study their band gap energy. The optical study shows a direct band gap of 2.90 eV for Bi2O3 films.