TiO2 gel films were deposited on three kinds of substrates: (1) a self-assembled monolayer (SAM) of octadecyltrichlorosilane (OTS), (2) a trimethylsilylated (TMS) glass surface and (3) a bare SiO2 glass surface using Ti(OC3H7i)(4)-derived titania sole. It was found that OTS SAM induces precipitation of anatase phase at a rather low temperature of 200 degrees C and accelerates anatase-to-rutile phase transformation when a mole ratio of H2O:Ti(OC3H7i)(4) as low as 0.5 was employed for sol preparation. These effects possibly result from the interaction between the ordered methyl groups of the OTS SAM and the hydrophobic groups of the titania polymers at the gel film/OTS SAM interface.