This study examines the effects of leadership styles and organizational culture on organizational effectiveness in Iranian sport organizations. 341 sport experts in the Physical Education Organization of the Islamic Republic of Iran and various sport Federations voluntarily filled out the Denison organizational culture survey (DOCS), multifactor leadership and organizational effectiveness questionnaires. Results of structural equation modeling (SEM) showed that transformational leadership has a significant positive influence on the effectiveness and organizational culture. Transactional leadership had a direct significant negative influence on organizational effectiveness and indirectly had a significant positive influence through organizational culture. In conclusion, the results showed that the proposed model has a good fit with this research data.