Seismic retrofitting of unreinforced masonry (URM) buildings is not a new concept and many techniques have already been used around the world for such improvements in their earthquake performance but limited technical literature is available on their seismic performance. This motivated the research study reported herein, which is one of only a few studies where full scale cyclic testing of strengthened URM walls was performed, and where the test walls were constructed using real or close replication of prevalent historic URM materials. Provided also is a comprehensive review of existing strengthening techniques, with a brief account on associated design concepts, implementation procedures and heritage conservation considerations. Additionally, a set of guidelines are also provided along with worked examples to facilitate a well-conceived seismic retrofit design.