The relationship between public opinion and foreign policy has given rise to a significant theoretical literature in the sociology of international relations. The main question is what the position of public opinion was in Iran’s foreign policy during the Pahlavi period, and how it reacted to the separation of Bahrain. It is an essential assumption that Bahrain’s position in the separation was reactive and limited due to the conditions of the international system, the regional order, and the country’s ruling political structure. The theoretical position of public opinion in non-democratic regimes is analyzed by examining the content of speeches, documents, and memoirs of official representatives to measure public opinion. The findings reveal that the position of public opinion is reflected in the protest of a small number of parliamentarians, some statements by national parties, and the significant role of Mohammad Reza Shah in this separation, albeit with concern for the judgment of Iranian society tomorrow.