The decline of the Iranian economy during the Qajar dynasty (1789-1925) can be attributed to a combination of internal and external factors. One of the main reasons for the economic decline was the centralized and inefficient governance of the Qajar rulers, who were not able to effectively manage the resources of the country. Many of the Qajar kings were weak or inept rulers, leading to corruption, mismanagement, and internal strife within the government. This lack of effective governance hindered economic growth and development in Iran.