Nanobiotechnology is a promising and appearing field of nanotechnology. In recent years, the necessity of making biocompatible materials for different applications in various area such as health, medicine, water treatment and purification, etc. caused more attention to this area. Today, green synthesis of different nanoparticles (NPs) has been extensively studied. However, less attention has been paid to manganese as a high-performance metal in various applications such as medicine, biomedicine, biosensors, water treatment and purification, electronics, electrochemistry, photoelectronics, catalysis, and etc. Manganese oxides (Mn-oxides) has wealthy structures such as MnO, Mn₅O₈, Mn₂O₃, MnO₂, and Mn₃O₄, and can be used in a variety of fields. Mn-oxide NPs potentially hold great promise for sustainable nanotechnology. This review focusses on the green synthesis, applications and future perspective of Mn NPs. Different methods of green synthesis of Mn NPs, including synthesis using plant extract, synthesis using microorganism, and low-temperature synthesis of Mn NPs have been investigated and presented. Structure, and size, of green synthesized Mn NPs via each method have been compared. Also, various applications of the green synthesized Mn NPs have been reviewed. Furthermore, the future perspective of green synthesis and applications of the green synthesized Mn NPs are expressed. Also, different applications explained for green synthesized Mn NPs are expressed as well as potential applications for green synthesized Mn NPs are suggested.