A nanoparticle is a nano-object with all three external dimensions in the size range of approximately 1–100 nm. Because of their small size, it can penetrate into the cell membrane and interfere in important cell functions. Zinc oxide nanoparticles (ZnO Nps) is one of the most commonly used types of nanoparticles that is widely used in different industries such as food additives, biosensors, resin production and electronic equipment, etc. Moringa oleifera (M.O.) extract has been shown to have strong antioxidant activity and decreases oxidative stress. The present investigation aimed to evaluate the toxic effects of ZnO Nps on sperm morphology and sex hormones (testosterone &FSH) and/or the ameliorative role of M.O. plant extract in vivo using male albino rats. The animals were divided into four main groups:Group1(control), group2 received M.O. extract (150mg/kg b.wt), group3 received suspension of ZnO Nps ( 7.5mg/kg b.wt) and group4 given ZnO Nps then were given M.O extract. The present results revealed that, the abnormalities in the sperm morphology and testosterone level induced by ZnO Nps were alleviated by the administration of M.O. plant extract (but no significant change in FSH level was observed).