This study investigates how the proportions of central courtyards affect ventilation flow within spaces adjacent to them. Eleven case studies were analyzed, including five with elongation along the prevailing wind, five with perpendicular elongation, and one square-shaped pattern (inspired by Golshan House in Bushehr). Significant differences were found in air velocity, air age, and inlet air flow between ground and first-floor rooms, with first-floor values generally higher. However, no significant difference was noted in the ventilation efficiency index between the two levels. The key finding is the correlation between ventilation efficiency and courtyard elongation aligned with the urban wind. Increased elongation in this direction enhances ventilation efficiency in interior spaces along the yard's main axis. This improvement arises because elongated courtyards function as channels for airflow, directing it towards room openings. In contrast, perpendicular elongation results in airflow colliding more with rigid walls, leading to energy loss and decreased air intake, thus lowering ventilation efficiency. Future research should focus on employing simulations for southern Iranian buildings and gathering data from additional courtyard houses in the area, highlighting the need to address both technical and socio-cultural challenges in preserving traditional courtyard housing in the hot, humid regions of southern Iran for better use by residents.