This chapter reviews recent advancements in magnesium-based composites, highlighting their promise for lightweight structural and industrial applications. It examines a broad spectrum of reinforcement materials, including hollow particulates such as alumina spheres, glass microballoons, and fly ash cenospheres, as well as emerging high-strength reinforcements like metallic glasses, metastable particles and high entropy alloys. Various fabrication routes—ranging from sub-atmospheric pressure infiltration and microwave-assisted sintering to powder metallurgy—are assessed for their influence on the mechanical, thermal, and corrosion performance of these composites. Particular attention is given to the role of reinforcement characteristics in tailoring density, energy absorption, compressive strength, and corrosion resistance. The chapter concludes by outlining future research directions, with emphasis on process optimization, sustainable feedstock utilization, and the development of next-generation high-performance composites for aerospace, automotive, and biomedical applications.