Bed-joint structural repointing is a widely used strengthening technique in historic masonry constructions, particularly in applications where the material appearance needs to be preserved. Despite its wide use, limited research is available on the effectiveness of this technique in masonry elements of greater thickness subjected to in-plane shear loading. In the reported study, the shear behavior of single-and triple-thickness masonry panels strengthened with Near Surface Mounted (NSM) steel bars was investigated. Masonry panels were built following the material characteristics and bonding types of a reference case and tested in diagonal compression. Two lime-based mortar mixes with different compressive strength were employed to assess the effect of existing mortar quality on the strengthening technique performance. The investigated parameters were the number of courses with reinforcement in single-thickness panels, and the depth of the reinforcement and number of the faces reinforced in those of triple-thickness. The technique proved effective in improving the shear deformation capacity regardless of specimen thickness and, in panels of triple-thickness, both the eccentricity (result of reinforcing one or two faces) and depth of reinforcement were observed to significantly affect shear behavior. CO 2021 Elsevier Ltd. All rights reserved.