Undoped and zinc-doped TiO 2 nanoparticles (Ti 1−x Zn x O 2 where x = 0.00–0.10) were synthesized by a sol–gel method. The synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and UV–VIS spectrometer. XRD pattern confirmed the tetragonal structure of synthesized samples. Average grain size was determined from X-ray line broadening using the Debye–Scherrer relation. The crystallite size was varied from 10 to 40 nm as the calcination temperature was increased from 350 to 800 °C. The incorporation of 3–5 mol% Zn 2+ in place of the Ti 4+ provoked a slight decrease in the size of nanocrystals as compared to undoped TiO 2 . The SEM and TEM micrographs revealed the agglomerated spherical-like morphology with a diameter of about 10–30 nm and length of several nanometers, which is in agreement with XRD results. Optical absorption measurements indicated a blue shift in the absorption band edge upon 3–5 mol% zinc doping. Direct allowed band gap of undoped and Zn-doped TiO 2 nanoparticles measured by UV–VIS spectrometer were 2.95 and 3.00 eV at 550 °C, respectively.