For the retrofitting of the existing masonry buildings, the use of external reinforcements on the structural elements represents an extremely relevant issue. Moreover, in seismic zones, the ancient buildings are prone to lateral forces triggered by earthquakes. Among different methods available, the use of carbon fibre reinforced polymer (CFRP) composites as a retrofitting provision represents a viable solution. CFRPs increase not only the overall strength of the systems, but also their ductility without a significant increase in mass. In this study, masonry triplet specimens were prepared with three bricks and two joints of mortar. Preliminarily, the mechanical properties of the selected mortar, including polyacrylonitrile fibers, were assessed through conventional three-point bending tests. Some masonry triplets were strengthened with CFRP fabric and subjected to shear tests, to assess the effectiveness of the external reinforcement. Samples were equipped with point sensors, such as LVDTs and a clip gauge, whilst two cameras were placed on the opposite large sides. The external reinforcement led to an increase of both the shear strength and the overall ductility: even in the presence of wide regions highly damaged, externally bonded CFRP exerted an important confinement, delaying the ultimate failure.