Green synthesis of nanoparticles has gained significant attention as an eco- friendly and sustainable alternative to conventional chemical methods. In this study, zinc oxide nanoparticles (ZnO NPs) were synthesized using the extract of black rice (Oryza sativa L. cultivar Karimundaga), which acts as a natural reducing and stabilizing agent due to its rich content of bioactive compounds. The formation of ZnO nanoparticles was confirmed through various characterization techniques such as UV–Visible spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results indicated that the nanoparticles were crystalline in nature with a predominantly spherical morphology and nanoscale size range. The antimicrobial activity of both aqueous extract and synthesised zinc oxide nanoparticles showed good zone of inhibition against bacteria namely Staphylococcus aureus & Pseudomonas aeruginosa and fungus namely Aspergillus flavus & Aspergillus Niger. The black rice possesses numerous phytochemicals and ability to produce nanoparticles have promising scope in research.