Transparent potassium titanyl phosphate (KTiOPO4) thin films were prepared by a sol-gel coating technique. The structural evolution of the KTP thin films was examined by means of DTA/TGA, FT-IR, XRD and SEM. The effect of UV irradiation on the crystallization behavior was investigated and it was found that the UV irradiation decreases the crystallization temperature of the KTP thin films and dried gels. The dielectric and electro-optic properties were evaluated. The dielectric measurement results show that the KTP thin films have a low dielectric constant of similar to 12 in the temperature range of 25-100 degrees C and frequency range of 1-1000 kHz. The electro-optic results indicate that the KTP thin films exhibit a quadratic electro-optic effect and may have potential applications for electro-optic devices.