This study examines two distinct methods for preparing zinc oxide nanoparticles (ZnO NPs): the chemical method and the green method. In the chemical method, zinc acetate and deionized water were used, while in the green method, the plant extract from the fruit of the Capparis spinosa plant was used. The nanoparticles of ZnO were analyzed using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR). ZnO nanoparticles prepared by chemical precipitation and biological methods were characterized using UV-Vis spectroscopy to analyze the absorption spectra. The FESEM images revealed the spherical shape of the nanoparticles. The sizes of the nanoparticles were experimentally calculated using XRD and FESEM. The particle size measured by the XRD pattern was 26 nm for the chemically synthesized ZnO NPs sample and 6 nm for the ZnO NPs sample prepared by green synthesis. FTIR spectra showed that the stabilizing agent made the particle surface inert. The results indicate that the ZnO NPs sample synthesized using the green method is better than the chemically synthesized samples. This comparative study highlights the influence of the capping agent and the resulting morphologies on surface area and recombination kinetics, while also noting that it can be used in medical applications due to its environmentally friendly method.