Fiber-reinforced polymers (FRP) composites are used as supplementary reinforcement to increase the in-plane shear capacity or to provide out-of-plane load-carrying capability of masonry walls and to modify the collapse mechanism in arches and vaults. In these applications, the efficiency of load transfer is limited by the debonding of FRP from the masonry substrate. In this paper, the debonding mechanism of FRP-masonry is experimentally studied. Experimental procedures and test specimens are designed to investigate the progressive debonding of FRP from brick and mortar substrates and relate it to the response obtained from the FRP-masonry interface. Surface displacements during debonding are obtained using digital image correlation. A one-dimensional numerical model is developed for predicting the fracture behavior along the FRP-masonry interface using the cohesive fracture parameters from the brick and mortar interfaces obtained from the computed strains. © 2072 American Society of Civil Engineers.