Highly oriented lead lanthanum titanate (PLT) thin films on MgO (100) and c-plane sapphire single-crystal substrates have been prepared using the sol-gel process. The orientation and the mechanism of the highly preferred oriented PLT films derived sol-gel process have been investigated. The sol-gel PLT films fabricated on MgO (100) and c-plane sapphire substrates grow preferentially with (100) and (111) crystallographic orientations respectively, regardless of the film thickness and La content. In addition, it is confirmed that the tetragonality of the PLT perovskite structure decreases with an increase of La content. The a-axis orientation of the sol-gel PLT film on MgO (100) substrate is controlled only by formation of the intrinsic tensile stress during the crystallization of the film.