The vast land of Iran throughout its ancient history has witnessed extensive population movements. Among these, the forced migration of ethnic groups and human communities is a phenomenon that, across different historical periods—especially in antiquity—was utilized by governments for political, military, economic, and even social reasons. Unlike voluntary migrations, which occur by the free will of peoples often driven by natural or economic factors, forced migrations were primarily imposed by ruling powers aiming to achieve goals such as internal cohesion, suppression of rebellions, strengthening parts of the empire, transferring labor forces, or promoting cultural-economic development. One of the eras during which this policy was pursued in a systematic and purposeful manner was the Achaemenid period. The Achaemenids, as one of the greatest empires in history, used forced migration as an effective tool to consolidate their authority, organize populations across various parts of the empire, and expand cultural and economic influence. This policy was not only instrumental in reinforcing central power but also played a significant role in shaping the administrative and social structures of the Achaemenid era. This study, employing a descriptive-analytical method based on library research, aims to examine various dimensions of the forced migration policy of ethnic groups in the Achaemenid period. The objectives, methods, and consequences of this policy—especially in key regions of the empire—along with the role of the relocated groups in the social, economic, and military structures of Achaemenid society, constitute the main focuses of this research. The study attempts to clarify the place of this policy within the Achaemenid governance system through a comprehensive perspective.