Crack‐free SBN (SrxBa1‐xNb2O6) thin films have been prepared by a sol–gel method with metal alkoxides. A homogeneous and stable precursor solution was obtained from Sr and Ba metal and Nb(OEt)5in ethanol with a key additive of ethoxyethanol. SBN (wherex= 0.5) powder crystallized to orthorhombic phase at 700°C, and then transformed completely to tetragonal phase at 1200°C. The formation of tetragonal SBN was observed on sapphire (R) substrates at 700°C, whereas the tetragonal phase began to appear in the powders at 1000°C. SBN films with highly preferred orientation were successfully synthesized on MgO (100) substrates