Polymer matrix composites (PMCs) have been shown to be an outstanding class of advanced materials, having great mechanical properties with high-strength fibers embedded in the matrix (aka binder), which both fibers and matrix can be properly arranged and controlled during the fabrication process. This chapter provides a comprehensive overview of the key features related to polymer matrix composites, encompassing their composition, manufacturing processes, properties, and diverse applications. The types of reinforcing fibers commonly used, such as carbon fibers, glass fibers, and aramid fibers, along with the variety of polymers employed as matrix materials. An in-depth examination of the interaction between the matrix and reinforcement is presented, highlighting the critical role both play in determining the overall performance of the composite. Manufacturing processes for PMCs are discussed, covering techniques such as spray lay-up, hand lay-up, filament winding, injection and compression molding, pultrusion, and autoclave curing. The influence of processing conditions on the final composite properties is discussed, addressing challenges and progresses in achieving better fiber arrangement, resin impregnation, and consolidation. The properties discussions explore the mechanical, thermal, and electrical characteristics of polymer matrix composites. An exploration of the factors affecting these properties, such as fiber orientation, volume fraction, and interfacial bonding, is undertaken. Finally, emerging trends and future directions in polymer matrix composites research are discussed, including advancements in nanocomposite technology. The discussion related to nanocomposite can be extended by researchers, engineers, and professionals looking for a deeper understanding of the design, fabrication, and utilization of nanocomposites in various applications.