The present study aims to understand the effect of mortar grade for bonding the masonry units, on the out-of-plane flexural behaviour of low-strength hollow concrete block masonry walls strengthened with welded wire mesh (WWM). Static out-of-plane flexural tests were performed on unstrengthened and WWM-strengthened specimens constructed with three different mortar grades representing strong, medium and weak mortar. It is observed that mortar strength do not have any profound effect on the flexural strength of unstrengthened specimens. The increase in mortar strength increases the flexural strength and ductility of WWM-strengthened specimens. However, there is insignificant difference in ductility between medium and strong mortared WWM-strengthened specimens. The failure of WWM-strengthened specimens is restricted to the masonry walls only suggesting overstrength of WWM. The comparison of experimentally evaluated flexural strength is also compared with existing analytical formulations displaying good agreement between experimental and analytical formulations.