In the present study, Al 2 O 3 -5 wt.% ZrO 2 nanocomposite powder was fabricated via the sol–gel method, and then the sintering behavior was investigated using various sintering aids (MgO, TiO 2 and MgO/TiO 2 ) at different temperatures. In this regard, the size and structure of fabricated powder, and hardness, fracture toughness and density of sintered samples were studied. The results of X-ray diffraction indicated the presence of α-alumina and tetragonal zirconia. Scanning electron micrographs revealed agglomerated nanometer-sized spherical particles ranging in size from 60 to 150 nm. Energy-dispersive X-ray mapping micrographs also demonstrated the homogeneous dispersion of zirconia in alumina. Moreover, density results indicated that using 0.5 wt.% MgO/0.5 wt.% TiO 2 produced the best results, as the relative density reached 95 % at 1 500 °C. Finally, it was observed that the presence of MgO and TiO 2 induces higher hardness and lower fracture toughness.