FRCM (Fiber-Reinforced Cementitious Matrix) and FRP (Fiber-Reinforced Polymer) composites represent an effective solution to strengthen existing concrete or masonry structures. Numerous experimental programs have been conducted in recent years to understand the potential benefits of different types of external reinforcement systems. FRCM systems are considered a suitable alternative to FRPs when drawbacks associated with the use of organic binders could compromise the strengthening intervention. Both FRPs and FRCMs are EBR (Externally bonded reinforcement), so the effectiveness of composite reinforced materials is influenced by the bond behaviour at different interfaces. The bond depends on many parameters, e.g. bond length, mechanical properties of substrate and reinforcement, environmental conditions, etc. Differently from FRPs, for which the bond between fiber and resin is of chemical nature thanks to the polymerization process of organic matrix, the interaction between inorganic matrix and fibers is mostly of mechanical type. In fact, inorganic binders can hardly impregnate all fiber filaments, which leads often to a debonding phenomenon at the matrix-fabric interface. The paper aims to furnish a contribution to the understanding of the physical phenomena that characterize the mechanical behaviour of FRCM materials and their bond with masonry structures. Different materials were used: two types of substrate representative of the historical and artistic heritage of Southern Italy (a sedimentary compact stone known as “Pietra Leccese” and a sedimentary porous stone; two types of mortar (cementitious and lime-based) and the same Basalt open-grid mesh. First, the mechanical properties of stone, mortar and FRCM were obtained through compressive, three-point bending and tensile tests; then the bond behaviour were investigated through single-lap shear bon test. The test results were collected and processed to evaluate both the bond strength and the failure modes.