This study reports the base-catalyzed aqueous sol-gel synthesis of zinc oxide nanoparticles. The solution was primarily comprised of zinc nitrate hexahydrate as a metal precursor, isopropyl alcohol and water as solvents, and glycerin as a stabilizing agent. The effect of calcination temperature on the structure and morphology of the prepared nanoparticles was investigated by varying the calcination temperature from 500 to 900 °C. The X-ray diffraction analysis, infrared spectroscopy, thermogravimetric analysis, and field emission scanning electron microscopy were employed to determine the crystal structure, surface functional groups, thermal stability, and surface morphology of the nanoparticles. The particle size was found to be directly proportional to the calcination temperature.