Green synthesis of nanoparticles is superior to physical and chemical methods as it is environment-friendly and cost-effective. The present study was carried out for inducing nanoparticles synthesis by zinc nitrate in the leaves extracts of olive. Further leaves extracts were evaluated for antiradical scavenging activity by 1, 1-diphenyl-2-picryl-hydrazyl assay. Morphological and structural properties of the synthesised ZnO nanoparticles have been characterised using UV-Vis spectrophotometer, FTIR, TEM, XRD and dynamic light scattering (DLS) analysis. Further, zinc oxide nanoparticles were evaluated for antiradical scavenging activity by capacity of total antioxidant assay. Synthesised ZnO nanoparticles were confirmed by the absorption maxima at the wavelength of 370 nm. TEM image revealed that ZnO nanoparticles were spherical with average size 41 nm. FTIR investigation suggested that the flavonoids, glycosides, proteins and phenols molecules can play an important role in the stabilisation of ZnO nanoparticles.