Ferroelectric Ba(SnxTi1-x)O-3 (BTS) thin films were deposited using a sot-gel process on LaNiO3-coated silicon substrates. The films showed a (100) preferred orientation depending on composition. The grain size decreased and the microstructure became denser with increasing tin content. The decreasing grain size with increasing tin may be attributable to lower grain-growth rates from the more slowly diffusing Sn4+ ion, which has a larger ionic radius than Ti4+. The ferroelectric phase transition temperature of Ba(SnxTi1-x)O-3 thin films with (a) x = 0, (b) x = 0.05, (c) x = 0.10, and (d) x = 0.15 occurs at about 150degrees, 45degrees, 28degrees, and 20degreesC, respectively. The highest K (figure of merit defined as K = tunability/tan delta = {[epsilon(0) - epsilon(E)]/epsilon(E)}/tan delta) was found for BTS thin films with x = 0.10, even though tunability was highest with x = 0.05. An increase of dielectric loss as compared with films with x = 0.10 produced a decrease in K value. The J-E characteristics were highly nonlinear and the electric field resulting in nonlinearity moved to lower electric fields with decreasing tin content.