The effect of sintering temperatures (1050-1200 °C) on the phase formation, microstructure and dielectric properties of a binary system lead-free ceramic bismuth sodium titanate–bismuth potassium titanate were investigated. 0.8Bi0.5Na0.5TiO3-0.2Bi0.5K0.5TiO3; BNKT ceramics were successfully fabricated using the combustion technique. XRD results showed the rhombohedral-tetragonal morphotropic phase boundary (MPB). The SEM results showed the average grain size (0.51-2.59 µm) of the samples increased with the increase of sintering temperatures. The sample sintered at the optimum temperature of 1150 °C exhibited the maximum density, shrinkage, dielectric constant at Curie temperature and remanent polarization (Pr) which were around 5.65 g/cm3, 17.75%, 5014 and 1.6 mC/cm2, respectively. The dielectric constant was related to the XRD results and density of the sintered ceramic.