In this paper, a green method is reported for synthesis and characterization of zinc oxide nanosheets using Olea europea leaf extract. ZnO nanosheets were characterized by UV-vis absorption spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The UV-vis absorption spectrum shows an absorption band at 374 nm due to ZnO nanosheets. XRD characterize the final product as highly crystalline ZnO with sizes in the range 18-30 nm. The SEM results reveal a presence of network of randomly oriented ZnO nanosheets or nanoplatelets with an average size of 500 nm and thicknesses of about 20 nm. This facile and green approach may provide a useful tool to large scale synthesis other nanoparticles that have potential biotechnology.