Plants have been used in the synthesis of metallic nanoparticles because they are more ecofriendly. These plant extracts also allow a controlled synthesis. Organic chemical solvents are toxic and require extreme conditions during nanoparticle synthesis. Plant extracts function as stabilizing, capping or hydrolytic agents. The ZnO nanoparticles are of significant interest as they provide many practical applications worldwide. The most important application of ZnO nano particles would be as antibacterial agents. The increases surface area and smaller size of these particles make them an ideal anti-bacterial agent. In this review, the overview of green synthesis of ZnO nanoparticles along with their antimicrobial activity was also reviewed. The green synthesis of ZnO nanoparticles from Azadirachta indica, Aloe vera, Murraya koenigii and Anisochilus carnosus were also highlighted. In this review, the available published data on AgNPs synthesis, the effects of different factors, characterization methods, properties, and their application are compiled and critically analysed.