This book gathers the proceedings of the 8th International Conference Mechanics of Masonry Structures Strengthened with Composite Materials (MuRiCo8), which was held in Bologna, Italy on June 25-27, 2025, and brought together scholars in the fields of modeling, testing, design, control, and health monitoring of masonry structures strengthened with composite materials. Conference topics include mechanics of historical masonry, performance of strengthened masonry with composites (including FRP, FRCM, TRM, and SRG systems), masonry/composite interaction, evolution of strengthening techniques, emergency measures for historical structures, and sustainability & circular economy (focusing on life-cycle assessment, recycling, and sustainable practices in composite applications). The contributions, which were selected by means of a rigorous international peer-review process, present a wealth of exciting ideas that will open novel research directions and foster multidisciplinary collaboration among different specialists.