<p>Friction stir processing (FSP) has established itself as a transformative solid-state technique for enhancing the surface properties of metals and alloys, particularly aluminum alloys, through microstructural refinement and reinforcement incorporation. Over the past 25&#xa0;years, extensive research has focused on developing aluminum surface composites (ASCs) via FSP, leading to significant improvements in mechanical strength, wear resistance, and corrosion performance. This review provides a comprehensive overview of FSP, tracing its historical development, fundamental principles, and the influence of key process parameters such as tool geometry, rotational speed, traverse speed, and processing strategies. A diverse range of reinforcement materials—including ceramics, metal oxides, and hybrid particles—has been employed to tailor the functional properties of ASCs. The review also highlights persistent challenges, including the uniform distribution of reinforcements, optimization of mechanical behavior, and the scalability of FSP for industrial applications. Furthermore, emerging directions such as hybrid reinforcement design, in situ process monitoring, and the integration of FSP with additive manufacturing are discussed, offering a roadmap for future advancements.</p> Graphical abstract <p></p>