Abstract <p>The increasing threat of antibiotic resistance and the demand for eco-friendly nanomaterials have driven significant interest in metal oxide nanoparticles, particularly cobalt oxide (Co₂O₃), due to their unique structural, magnetic, and biological properties. In this study, Co₂O₃ nanoparticles were synthesized via chemical precipitation and functionalized with curcumin, a bioactive polyphenol with known antimicrobial and therapeutic potential. The nanomaterials were characterized using X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), confirming the successful formation of spinel-phase Co₂O₃ and its surface modification by curcuma. Antibacterial activity was assessed against both Gram-positive (<i>Staphylococcus aureus</i>) and Gram-negative (<i>Escherichia coli</i>) bacteria using the disk diffusion method. Co₂O₃ nanoparticles exhibited moderate antimicrobial activity, which was notably enhanced upon functionalization with curcuma. Furthermore, combining nanoparticles with conventional antibiotics led to significantly increased inhibition zones, indicating a synergistic antibacterial effect. These findings highlight the potential of curcuma-functionalized Co₂O₃ nanoparticles as multifunctional agents in nanomedicine, environmental remediation, and pharmaceutical applications, offering a promising strategy for combating antibiotic-resistant pathogens while preserving beneficial microbiota.</p>