Zinc oxide nanoparticles (ZnO NPs) were successfully synthesized using an eco-friendly green approach mediated by the aqueous leaf extract of Colocasia esculenta. The nanoparticles were characterized through UV–Visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR). The antimicrobial potential of the biosynthesized ZnO NPs was evaluated against selected fungal and bacterial pathogens. XRD revealed a wurtzite hexagonal ZnO structure with an average crystallite size of 17.56 nm. FTIR spectra indicated phenolics, amines, and amides as capping and stabilizing agents. The antimicrobial efficacy of the ZnO NPs was tested against selected fungi: Aspergullus tamari, Penicillium marneffei, Rhizopus stolenifera, Fussarrium solani and Rhizopus nigrican and bacteria: Escherichia coli, Erwinia carotovora, and  Pseudomonas aeruginosa. The ZnO NPs exhibited significant antimicrobial activity, showing inhibition from 43.33 % (moderate) to 85.54 % (effective). These findings highlight the potential of ZnO NPs as cost-effective, eco-friendly alternatives for antimicrobial formulation.