Metal oxide nanoparticles have gained popularity owing to their unique properties. Recently, metal oxides, particularly rare-earth metal oxides, have been explored and used in several areas. Samarium oxide (Sm2O3) amongst other rare-metal oxides is no exception. It has a band gap of about 4.3 eV and suitable dielectric properties. Different morphologies and structure-based Sm2O3 and Sm2O3-based nanostructures have been fabricated using different synthesis methods such as precipitation, hydrothermal, combustion, green synthesis, etc. Additionally, various applications of Sm2O3 and Sm2O3-based nanostructures have also been investigated. The reported properties impact the response towards the applications such as photocatalysis, sensors, CO conversion, and biological applications. Therefore, in this perspective, different synthesis methods, characteristics, mechanisms, and varieties of applications of Sm2O3 and Sm2O3-based nanostructures have been investigated and discussed.