Ba(Sn0.15Ti0.85)O-3 (BTS) thin films were grown on Pt(2 0 0)/Ti/SiO2/Si(1 0 0) and Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates by a sol-gel processing technique, respectively. The dependence of microstructure and dielectric properties on film orientation has been studied. The BTS thin films directly grown on Pt(2 0 0)/Ti/SiO2/Si substrates exhibited highly (1 0 0) and (1 1 0) preferred orientation depending upon concentration of the precursor solution. The BTS thin films directly grown on Pt(1 1 1)/Ti/SiO2/Si substrates exhibited highly (1 1 1) preferred orientation. The dielectric constant of the BTS films with (1 0 0), (1 1 0) and (1 1 1) preferred orientation was 485, 240 and 510, respectively, measured at a frequency of 1 MHz and at room temperature. The tunability of films with (1 0 0) preferred orientation was 36.10%, which was higher than that of BTS thin films with (1 1 0) and (1 1 1) preferred orientation at the frequency of 1 MHz with an applied electric field of 200 kV/cm. This work clearly reveals the microstructure and dielectric properties of BTS thin films exhibited a strong sensitivity to crystal orientation. (C) 2007 Elsevier B.V. All rights reserved.