Thin films of anatase titanium dioxide (TiO2) were prepared on slide glass substrate surfaces by a titanium alkoxide hydrolysis operation, and the hydrophilicity and the transparency of their films were examined. The contact angles of water and the transmittances of visible light for their substrates changed with the duration of tetraethyl orthotitanate (TEOT) hydrolysis operations. They were influenced by the thickness of the films and the size of the deposited particles on the silicon dioxide-coated slide glass substrate surfaces. The contact angles also changed with the irradiating duration of ultraviolet light. When acetylacetone was added to a TEOT solution, the contact angles on the thin films became larger and the transparency was better during the same duration of TEOT hydrolysis operations. On addition of acetylacetone, nucleation of TiO2 particles at the initial stages of TEOT hydrolysis operations was restrained and, subsequently, the supersaturations of TiO2 in the solution became comparatively higher in the later stages of TEOT hydrolysis ones.