Phase change materials (PCMs) are known for storing thermal energy by the virtue of their inherent latent enthalpies. Careful introduction of PCMs as thermal mass along with external insulation is likely to naturally ventilated buildings and reduce cooling energy consumption in air conditioned buildings. Form stabilized phase change materials integrated with building envelope promises to offer ease of construction without encroaching on valuable floor space occupied by building structure. This study evaluates influence of PCMs on thermal performance of buildings in hot and dry climate of India. In first phase, study relied on whole building energy performance simulation to determine potential benefits of phase change materials and to identify suitable thermal characteristics of PCMs. Based on simulation results, two PCM compositions were developed by manufacturer and characterized in the laboratory. Based on measured characteristics, one composition was selected to develop ceiling tile prototype for deployment in experimental setup. In second phase, PCM ceiling tiles were installed in externally insulated naturally ventilated room measuring 3.3 meter by 3.3 meter by 3.3 meter. Fully instrumented room capable of measuring various indoor and outdoor environmental conditions provided insights into PCM effectiveness. Study quantifies benefits of PCM on thermal comfort conditions inside naturally ventilated buildings using simulations and experimental setup. Study also provides guidance to determine most appropriate melting and freezing point of PCM, which helps in manufacturing. A collaborative approach between R&D institute and PCM manufacture provide valuable results leading to understanding of PCM performance in India.