With the onset of World War II (1939-1945 AD), the Iranian government immediately declared its neutrality towards the warring parties in a statement. However, following Germany's invasion of the Soviet Union in June 1941 AD, the Allied forces occupied Iranian territory. Numerous studies have examined the factors influencing the occupation of Iran in World War II. Nevertheless, these studies have paid less attention to the geopolitical requirements of Iran's occupation within the framework of the concept of classical geopolitics. In the classical geopolitical view, the interaction between the economic, security, and cultural components of countries determines their unique geopolitical destiny. Especially regarding the realization of a country's neutrality in international conflicts, the geopolitical requirements of that country play a decisive role. Accordingly, the main question of the present research is: how did the combined performance of geoeconomic and geocultural factors, along with the requirements of Iran's geostrategic position relative to the belligerent parties, lead to the occupation of Iran by the Allies in World War II? In order to answer this question, this research, using a descriptive-analytical method and relying on historical documents, examines the causes of the Allied occupation of Iran during this period within the framework of the classical geopolitical perspective. The findings of this research indicate that from September 1941 AD, the survival of the Soviet Union against the German invasion was practically impossible without access to Allied aid through Iran. Furthermore, the occupation of Iran ensured the supply of needed fossil resources for the Allies, especially Britain. Also, from a cultural geopolitical perspective, the identification of the nationalist thought of Reza Shah Pahlavi with Nazi ideology played an effective role in the violation of neutrality and the occupation of Iran by the Allies