Composite materials that are constructed of textiles with high mechanical strength and embedded in a mortar matrix (also known as textile reinforced mortars (TRMs)) have received significant attention as they are a promising material for strengthening historical masonry structures because of their superior sustainability and physical compatibility with masonry substrates. In this paper, three types of TRMs, which include steel, carbon and basalt textiles embedded in cement mortar matrices used as shear reinforcement of masonry panels, are experimentally investigated. The experimental component consists of the mechanical characterization of TRMs by testing 16 TRM coupons under tensile loading, and evaluation of their strengthening effect on the shear behaviour of an unreinforced masonry wall by testing 2 unreinforced and 5 strengthened masonry panels under diagonal compression loading. Finally, the contribution of TRM in strengthened panel is evaluated by analytical methodologies and a criterion to design the TRM for strengthening masonry wall is proposed.