The nanoparticles (NPs) of titanium dioxide (TiO2) were synthesized using sol-gel method. This method was preferred as it gives NPs with uniform particle size, surface properties, control of reaction time and temperature, easiness in operation and of low cost. The synthesized gel was annealed at different temperature for 2 h in a muffle furnace between temperature 400 and 900°C. Fourier Transform Infrared spectroscopy showed Ti-O-Ti stretching vibrations at wavenumber 668 and 1033 cm-1 and Ti-O at 435 and 416 cm-1 in line with the tetrahedral structure of TiO6. Structural properties were studied using X-ray diffraction (XRD) which displayed anatase and rutile phases with peaks 105 and 101 respectively. Change of phase from anatase to rutile occurred at 600°C characterized by peak 101. The crystallite size calculated using Debye-Scherrer equation is of the range between 10.83 to 23.90 nm for 400°C to 900°C respectively. Crystallite size was found to be directly proportional to XRD peak intensity and inversely proportional to Full Width at Half Maximum. Scanning Electron Microscope confirmed the improvement of the nanoparticles morphology with no agglomeration and aggregation at 800°C. Kubelka-Munk and Tauc equations were employed in the optical analysis and the optical band gap value reduced from 3.50 eV to 3.26 eV for 400°C and 900°C respectively.