Nickel Oxide (NiO) thin films have been grown by Successive Ionic Layer Adsorption and Reaction (SILAR) method on glass substrates at room temperature. Grown NiO thin films subsequently annealed from 200 degrees C to 400 degrees C for 0.5 h. The effect of annealing temperature on the structural, morfological, molecular and optical properties were analyzed. NiO thin films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), fouirer transform infrared spektrofotometre (FTIR) and UV-vis spectrophotometer respectively. The crystal and surface properties of NiO thin films developed with annealing temperature. The energy band gap values were reduced from 3.3 to 3.11 eV depending with annealing temperature.