Electro-optically active and highly transparent lanthanum-modified lead zirconate titanate [PLZT, Pb0.91La0.09(Zr0.65Ti0.35)O3] films over 1 µm thick were deposited directly on glass substrates using an aerosol deposition method. An optical transmittance of 70% at the wavelength of 800 nm was obtained for a 4.5-µm-thick PLZT film with a reflection loss of 20% at the film and substrate surfaces. A quadratic electro-optical response with a slim loop was observed, consistent with the expected bulk response. The quadratic electro-optical coefficient was 2.5×10-18 m2/V2, comparable to that of films deposited on buffer layers using a sol-gel method. These results indicate that aerosol deposition provides a superior method for depositing the layers of optical devices.