Highly crystalline and transparent Eu-doped Gd2O3 thin films were produced through a modified sol-gel method that did not require the use of any chelating agent. The effect of the atomic fraction of Eu 3+ ions ('x' =0.05-0.30) on the structural, optical and luminescent properties has been studied. X-ray diffraction studies showed the preferential growth of Gd2-xEuxO3 thin films along the (400) plane corresponding to the cubic phase. UV-vis measurements revealed the high film transparency of the films in the visible region and a band gap value of 5.3eV. It has also been observed that the luminescence properties of the films were strongly dependent on both, the excitation wavelength and Eu concentration; the most efficient excitation conducive to red luminescence was achieved at the absorption band of Gd2O3 host (229nm). Under this condition all films exhibited strong red emission that is characteristic of Eu3+ ions. The emission intensity was also dependent on the doping level; the most intense luminescence was obtained at 'x'=0.15. The drop in the luminescence intensity observed for 'x' values higher than 0.15 was attributed to quenching concentration effect. © 2009 Materials Research Society.