Magnesium alloys have emerged as promising light weight materials due to their low density, high specific strength, excellent machinability, and superior damping capacity, making them ideal for aerospace, automotive, and electronics applications. However, broader use of magnesium alloys is limited by poor thermo-mechanical performance, corrosion susceptibility, and low formability at room temperature. The addition of rare-earth elements such as gadolinium, yttrium, and neodymium has meaningfully improved these limitations, enhancing the overall performance of magnesium alloys. This review highlights recent advancements in rare-earth magnesium alloys, focusing on their improved thermo-mechanical properties, microstructural evolution, crystallization behavior, and texture development. Herein, strengthening mechanisms associated with rare-earth additions are discussed in detail. Furthermore, the article explores growing relevance of these alloys in advanced applications, including biomedical implants, IoT devices, aerospace structures, defense systems, and general engineering. With their enhanced mechanical and functional properties, rare-earth magnesium alloys represent a new generation of high-performance, functional materials poised to drive innovation across multiple technology sectors.