Advantage of small amount (0.5 mol%) of holmium ion (Ho+3) substitution in the sodium bismuth titanate (NBT) on its electrical properties had been highlighted. Na0.5Bi0.5TiO3and Na0.5Bi0.495Ho0.005TiO3(NBT-Ho) had been synthesized by using solid state technique. In the dielectric properties, depolarization temperature (Td) and temperature at maximum dielectric constant (Tm) were increased to ˜180 °C and ˜ 355 °C, respectively in compared to Td˜165 °C and Tm˜ 325 °C of pure NBT. In addition, improved insulating nature was found in holmium substituted ceramic, which was confirmed by room temperature leakage current density versus electric field (J-E) measurement and temperature dependent impedance analysis. It showed five times lesser leakage current density at ˜45 kV/cm over its parent ceramic NBT. Leakage current density of holmium substituted NBT in the function of electric field (J versus E graph) displayed that electrical conduction follows the ohmic behavior up to ˜ 7.5 kV/cm electric field, and thereafter, up to ˜ 20.1 kV/cm, space-charge limited conduction mechanisms (SCLC) became to dominate. Moreover, enhanced electromechanical coupling coefficient (kp˜18.67%) in the NBT-Ho in comparison to pure NBT (kp˜18.17%) was obtained. © 2020 Elsevier Ltd. All rights reserved.