Zinc oxide (ZnO) nanoparticles have a great interest due to their important electrical and optical properties that have the potential to bring benefits to many areas of research and application. The present study is the preparation of zinc oxide nanoparticles using Sol–gel chemical method and the preparation using surfactant. The surfactant used was triethanolamine (TEA). Surfactant and unsurfactant ZnO nanoparticles were prepared to accomplish a comparative study. the properties of the prepared ZnO NPs have been characterized with the aid of many analytical techniques including Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and UV–Vis spectroscopy. The surfactant used was triethanolamine (TEA). The obtained ZnO NPs were spherical with average size of 79 nm without agglomeration. FTIR spectra showed the adsorption of TEA on the ZnO surface. The results of the UV-vis studies showed a decrease in band gap energy of 2.23eV as compared with the unsurfactant value of ZnO (3.28eV). Surfactant ZnO nanoparticles showed larger crystallite size and smaller bandgap in contrast to unsurfactant ZnO nanoparticles. TEA can use for prepare of nanomaterials with different properties for specific applications.