Anatase TiO2 nanoparticles were treated with oleic or stearic acid, and the dispersion behaviour of the treated and non-treated nanoparticles in non-polar solvents was studied. The dispersion stability of the TiO2 nanoparticles was also visually examined. It was found that stearic acid covers the nanoparticles surface more than oleic acid. Moreover, the influence of the UV irradiation on the chemical structure as well as the dispersion behaviour of the oleic acid and stearic acid treated nanoparticles was investigated. The results showed that the stearic acid treated nanoparticles provide a better dispersion performance after UV irradiation. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.