Green synthesized Zinc oxide (ZnO) nanoparticles have wide variety of applications which includes medical, industrial, cosmetic, agricultural etc. ZnO nanoparticles are multifunctional and its efficiency varies based on their particle size, surface morphology, pH, concentration and synthetic methods. Especially in biomedical area, ZnO nanoparticles are safe to human and also exhibits attractive antibacterial and antifungal properties. ZnO nanoparticles are also used as anticancer and anti-diabetic agents with much higher efficiency. It have also been emerged as promising drug carrier and thus been effectively used for transportation of drugs to target sites. Among the different synthesis methods, the green synthesized ZnO nanoparticles are noticed to be more active and selective especially when their biological activities are concern. ZnO nanoparticles also possesses very good photo-oxidizing and photo catalytic properties. This review elaborates ZnO nanoparticles synthesis methods and its antidiabetic and anticancer activities. © 2025 The Authors