The increasing energy consumption in contemporary buildings in Shiraz, along with the declining consideration of vernacular and climate-responsive architectural principles, has highlighted the urgent need to reconsider current building design strategies. In this context, passive architecture, which relies on climatic conditions and indigenous knowledge, is recognized as one of the most effective approaches to improving energy efficiency and reducing dependence on mechanical systems. However, many of its fundamental principles have been neglected in the design process of modern buildings. This study aims to identify and analyze the key factors affecting energy consumption optimization in the passive architecture of Shiraz. The research adopts a qualitative review approach, and the required data were collected through a systematic review of library resources, peer-reviewed scientific publications, and documents related to the vernacular architecture of Shiraz. Data were analyzed using a descriptive–analytical method. The findings indicate that seven key components, including appropriate building orientation, an optimal window-to-wall ratio, central courtyards, deep verandas (Iwans), sand catchers, wind catchers (Badgirs), and the use of indigenous building materials with high thermal mass, have the greatest impact on reducing energy consumption. Furthermore, the results reveal that the integrated application of these components can significantly reduce the demand for active heating and cooling systems. Therefore, the proposed framework can serve as a practical guideline for designing climate-responsive buildings and enhancing energy efficiency in Shiraz, providing valuable insights for architects, researchers, and building designers.