The study aimed to synthesize zinc nanoparticles (Zn-NPs) using an aqueous extract derived from Acacia modesta Wall. leaves. Several characterization techniques were employed to confirm the successful formation of zinc nanoparticles. UV-visible spectrophotometry indicated a peak at 374 nm, validating the bioreduction process. Scanning electron microscopy (SEM) was utilized to analyze the morphology, transmission electron microscopy (TEM) to determine particle size and shape, X-ray diffraction (XRD) for crystalline structure analysis, energy-dispersive X-ray spectroscopy (EDX) for elemental composition and Fourier-transform infrared spectroscopy (FTIR) to identify functional groups. The synthesized Zn-NPs demonstrated remarkable antibacterial activity against Escherichia coli (95% inhibition) and moderate antifungal activity against Candida albicans (70% inhibition). In phytotoxicity tests, the Zn-NPs exhibited a 55% reduction in the growth of Lamina minor at the highest dilution (1000 µl). Based on these findings, the study concluded that the green-synthesized Zn-NPs hold great potential as effective antibiotics against pathogenic bacteria and could be utilized in various industrial and agricultural applications.