The use of nanoscale fertilizers to boost crop output has increased in recent years. Nanoparticles (NPs) can stimulate the biosynthesis of bioactive compounds in plants. It is the first report on biosynthesized manganese oxide nanoparticles (MnO-NPs) that mediate in-vitro callus induction of Moringa oleifera. To achieve better biocompatibility the leaf extract of Syzygium cumini was used to synthesize MnO-NPs. Scanning electron microscope SEM revealed spherical shaped morphology of MnO-NPs with an average diameter of 36 ± 0.3 nm. Energy-dispersive X-ray spectroscopy (EDX) depicted the formation of pure MnO-NPs. X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) authenticate the crystalline structure. UV-visible absorption spectroscopy depicted the activity of MnO-NPs under visible light. The biosynthesized MnO-NPs were concentration-dependent and revealed promising results in callus induction of Moringa oleifera. It was found that MnO-NPs enhance callus production of Moringa oleifera and keep the callus infection free by providing an optimum environment for rapid growth and development. Therefore MnO-NPs synthesized through the green process can be utilized in tissue culture studies. This study concludes that MnO is one of the essential plant nutrients that have tailored nutritive properties at a nano scale.