The rise of nanotechnology has brought to the world a new potential and the use of different nanomaterials has revolutionized both the industrial and biomedical worlds with the broader perspective of what humanity can achieve through material manipulation at the nanoscale. Nanoscale particles possess distinct characteristics which advances in exploring and exploiting the uses of nanostructured materials. Due to the high surface to volume ratio and high reactivity there is a great potential for metal and metaloxide nanostructures. Synthesis of nanoparticles by physical and chemical methods are costly and toxic to the environment. Use of biosynthesis provides advancement over physical and chemical methods and may lead to the development of clean, non-toxic and environmental acceptable procedures which involves organisms ranging from bacteria to fungi and also plants. Green synthesis of metal nanoparticles is an expanding area of research and in the current study, Murraya koenigii i.e., Curry leaf powder was used for the green method by which manganese oxide nanoparticle synthesis was developed. Murraya Koenigii which belongs to Rutaceae family has found to be potent antioxidant due to high concentrations of carbazoles, a water soluble heterocyclic compound and also responsible for the reduction of metal ions. The present study focus on the development manganese oxide nanoparticles from the leaf extract of murraya koenigii where potassium permanganate act as precursor. Crystal phase identification of manganese oxide nanoparticles was studied by X-ray diffraction analysis and optical characterisation was carried out using Uv-Vis spectrophotometer.