Nanoencapsulated bioactive compounds applied as nanofertilizers not only improve crop yield but also curtail excessive use of inorganic fertilizers, thereby reducing environmental pollution. Owing to their excessively small size, they can penetrate inside the plant system through stomata, root or seed coat and have the ability to pass through cell walls or plasmodesmata with the cell sap. They are equipped with high surface-to-volume ratio, target delivery and thereby imparting biotic and abiotic stress resistance to the plant ecosystem. Different metals and metal oxides are generally used as nanofertilizers to boost crop production by maintaining soil biota. Out of these, ZnO nanofertilizers are mostly used nanofertilizers owing to their diverse potentiality in agriculture and allied fields. The present chapter reviews the importance of zinc as a micronutrient, synthesis of ZnO nanofertilizers, method of application, uptake mechanism by plant systems as well as antimicrobial activity of ZnO nanofertilizer to protect plant health and to meet the global food demand.