BaTiO3-MgO Composites with various compositions were fabricated by using a Spark Plasma Sintering (SPS) method. BaTiO3-MgO Composites with very high density were successfully sintered by SPS method. From the experimental results of as-sintered composites, Vickers hardness decreased and fracture toughness increased with increasing BaTiO3 content. The higher fracture toughness of BaTiO3-MgO composite with 10 vol% BaTiO3 content was achieved compared to monolithic MgO. In order to investigate the effect of piezoelectric BaTiO3 particles dispersed in MgO matrix, fracture toughness of the polarized composites was also evaluated. After polarization, fracture toughness of the BaTiO3-MgO composites was improved and higher than that of monolithic MgO, while polarization induced distinct anisotropy in fracture toughness between parallel and perpendicular directions to the poling direction.