This paper presents the results of a laboratory investigation carried out on reinforced mortar plates. Reinforced mortar plates are often applied for shear reinforcement of wall panels. Different reinforcement materials have been embedded into the mortar plates: GFRP (Glass Fiber Reinforced Polymers) grids, fiberglass fabrics and welded steel-wire meshes. This is the first stage in the development of a new type of GFRP-reinforced mortar jacketing, that will provide a solution to enhance the lateral capacity of historic buildings. Such reinforced plates can also be used in applications on new masonry constructions where buildings with damaged or cracked wall panels need to be repaired or retrofitted. The mortar plates were built from commercially available GFRP grids and fabrics that were embedded into the mortar to form a reinforced-mortar square structure of 1 m with a thickness of 30 mm. The plates were tested in the laboratory, under quasi-static patch loads that exceeded the expected seismic loads. The goal of the testing program was to assess the design and construction techniques used, with a view to designing the reinforcement of a historic building. The laboratory tests demonstrated that the GFRP-reinforced plates had sufficient stiffness and strength to function effectively. By comparing the results with the more traditional steel-wire mesh reinforcement, it was also possible to perform a comparative analysis.