Aluminum–boron carbide (Al–B₄C) metal matrix composites (MMCs) are lightweight materials offering high specific strength, stiffness, and high neutron-absorbing capability due to their high boron content. However, their practical use in aerospace and nuclear applications has been limited by the difficulty of joining these ceramic-reinforced aluminum materials using conventional fusion welding. Fusion welding often leads to the decomposition of B₄C, formation of brittle intermetallic phases, and weld defects such as porosity and low joint efficiency. This bibliographic review examines friction stir welding (FSW), a solid-state joining process well-suited for aluminum alloys. Key findings include: (1) FSW avoids formation of deleterious Al–B–C compounds by keeping the process below the melting point, preserving B₄C particles and producing joints with near-parent metal strength; (2) appropriate FSW process parameters such as tool design, rotational and travel speeds, and forging force critically influence particle distribution and weld integrity; (3) FSW joints exhibit refined microstructures, uniform B₄C particle dispersion, and minimal defects, leading to high weld quality; (4) the mechanical properties of FSWed Al– B₄C joints are high –achieving 90–100% of base metal tensile strength, or even exceeding it in some cases – with improved ductility relative to fusion welds. FSW emerges as an effective joining method for Al– B₄C composites, enabling high-strength welds without compromising the composite’s microstructural integrity. Potential research directions include optimizing FSW tool materials to mitigate tool wear on abrasive B₄C, and further exploring parameter windows for improved mechanical performance.