In this study, Sb2O5 doped (Bi0.5Na0.5)TiO3-(K0.5Na0.5)NbO3 ceramics have been prepared by a conventional mixed-oxide method via vibro-milling technique. The phase formation behavior, microstructure and electrical properties have been investigated as a function of Sb2O5 content. It is shown that the addition of Sb2O5 can improve both density and electrical properties in BNT-KNN ceramics. While the dielectric constant and ferroelectric properties improve with addition of Sb2O5, the dielectric loss tangent of the ceramics does not change significantly. Though at high doping level of 1.0 mol % the density of ceramics decreases, the dielectric constant increases. Improved electrical properties obtained in Sb2O5-doped KNN-BNT are likely due to the coexistence of tetragonal and orthorhombic phases near the orthorhombic-tetragonal polymorphic phase transition at room temperature. Copyright © Taylor & Francis Group, LLC.