Abstract: A titanium oxide sol comprising a disperse medium and generally rectangular, non-spherical particles of titanium oxide dispersed in the disperse medium, with narrow scatteres in particle size and configuration. The sol is excellent in dispersibility, long-term stability and light-resistance and, is stable in a wide pH range without causing agglomeration. Moreover, it is excellent in absorbance of ultraviolet ray and in transmittance of visible light. The sol may be prepared by a process wherein hydrogen peroxide is added to a gel or sol of hydrated titanium oxide to dissolve the hydrated titanium oxide in said gel or sol, and the resulting aqueous titanic acid solution is heated in the presence of at least one compound selected from inorganic compounds of metals belonging the Group II, III, IV, V, VI and VIII of the periodic table.