Nanocrystalline SnO2 particles have been synthesized by a simple sol-gel method. The structural and optical properties of these SnO2 particles are investigated using X-ray powder diffraction, transmission electron microscopy, UV-visible absorption, and photoluminescence spectroscopy. The oxygen-vacancies-related photoluminescence of pure, cerium-, and manganese-doped SnO2 nanoparticles was systematically investigated. The origin of the luminescence is assigned to the recombination of electrons in a conduction band with holes in the V-o(..) center. Experimental results reveal that increasing calcining temperature can decrease the oxygen-vacancies-related luminescence intensity of the sample. After introducing Ce3+/Mn2+ ions into the host, the oxygen-vacancies-related luminescence has been enhanced remarkably resulting from the formation of many more oxygen vacancies. The dependence of the oxygen-vacancies -related luminescence intensity on the Ce3+/Mn2+ concentration is also discussed.