Estimation of the lateral load-carrying capacity of unreinforced masonry (URM) buildings is essential for their design, vulnerability assessment, and rehabilitation. Lateral strength of URM buildings can be assessed using experimental studies or numerical simulation, but conducting such studies on full-scale building specimens is expensive and requires huge computational effort and input data, which is not easily available. Therefore, the availability of test results and data is scarce in many developing countries having a huge concentration of URM buildings. Moreover, the quality and strength of masonry found in these countries are inferior to those found in some developed countries where data are available. This results in under-developed design codes and thus improper design and construction of URM buildings in seismically active regions of many developing countries. Therefore, simple analytical methods are required to be developed for the estimation of lateral load-carrying capacity of URM buildings with the help of systematic experimental and numerical studies on full-scale specimens. The paper presents a comparative assessment of the lateral strength of a URM building using experimental, analytical and numerical approaches. Pseudo-static in-plane cyclic tests were carried out over three full-scale URM walls with different opening configurations followed by testing of a single story URM building having a single room, constituting the walls, which were already tested. The walls and a building were then numerically analyzed in Abaqus and Strand7 to estimate the lateral load-carrying capacity. The lateral strength of individual walls was also estimated analytically using several existing methods. Finally, the effectiveness of combining the lateral strength of individual walls to estimate the lateral strength of full URM building was assessed that can be handy to the practicing engineers.