Various substrates were investigated for use in crystal-oriented PbTiO3 thin films deposited by rf magnetron sputtering. In fabricating ferroelectric thin films with controlled crystal orientations, a close relationship was found between the thermal expansion coefficients of the films and substrates. Where the thermal expansion coefficient of the substrate was larger than that of the film, as in the case of a single-crystal MgO substrate, horizontal compressive mechanical stress along the plane of the film led to a c-axis-oriented film. Conversely, where the thermal expansion coefficient of the substrate was smaller than that of the film, as in the case of a quartz glass substrate, tensile stress in the film gave rise to an a-axis-oriented film. The Curie point of the film material determined the amount of mechanical stress present during cooling. Based on the above, new substrates of glass ceramics for use in c-axis-oriented films were developed.