Fiber Reinforced Cementitiuos Mortars (FRCM) are a relatively new class of reinforcement used in conservation engineering. However, the structural response of shear walls reinforced with non-isotropic composite material nets, bonded with relatively low-strength and non-elastic mortar matrices is difficult to study with numerical models. The reliability of numerical models could be improved if experimental data was available from full size testing. However, such data is expensive to obtain as large specimens are needed. In this paper, an experimental campaign was carried out at the laboratory on 12 full size wall panels. These were tested in diagonal tension to assess their shear behavior in unreinforced and FRCM-reinforced configurations. Some manipulation of the data is required in order to interpret the experimental results, but diagonal tension testing has many advantages over other testing methods to study the shear behavior of masonry walls. In general the results have demonstrated that FRCM strengthening of shear walls is an effective retrofitting method. Different reinforcement schemes (single- and double-sided retrofits) and bonding inorganic matrices have been studied. Lastly, a two-step non-linear numerical procedure, calibrated with characterization test data and benchmarked on the laboratory outcomes (i.e. full scale testing), has been also implemented to define an effective tool for predicting the shear behavior of reinforced walls.