This work compares the changes in optical and structural properties of cerium oxide (CeO₂) when doped with different concentrations (3%,5%,7%, and 9%) of two oxides, In₂O₃ and Eu₂O₃. X-ray diffraction and spectrophotometry were employed in the visible, ultraviolet, and near-infrared regions. The findings demonstrated that CeO₂ doped with In₂O₃ and Eu₂O₃ thin films were polycrystalline and had a cubic structure. The crystal size increased from 20.5 to 32.15 when Eu₂O₃ doping ratio increased from 0% to 7% and then decreased to 28.46 nm at 9%. While the crystal size showed an increase from 20.5 to 21.42 nm with the increase of the In₂O₃ doping ratio, while the lattice constant measured for cubic CeO₂ changed opposite to that. The optical measurement showed that Eu₂O₃ and In₂O₃ doped CeO₂ thin films have a direct band gap with allowed transition with 3.0 eV for the undoped CeO₂. The band gap energy changed in a non-regular manner with the increase of the doping ratio of both oxides. The minimum band gap energy was 1.2 eV obtained for 7% Eu₂O₃ doped CeO₂ thin film, and the minimum band gap energy was 1.4 eV obtained for 9% In₂O₃ doped CeO₂. These results qualify them for use as absorbers in solar cell applications.