The coup of August 19 is considered one of the most significant points in the contemporary history of Iran, which brought about extensive socio-economic changes and profound intellectual and cultural transformations in Iranian society. This coup defined the country’s social and economic system and foreign relations in a context completely different from the period of nationalization of the oil industry, and thereby opened a new perspective in the thinking and practice of Iranians. In this regard, this article seeks to analyze the two interrelated aspects of the causes of its occurrence and its results and consequences by using the descriptive-analytical method and library resources. Accordingly, the research findings are presented by asking the question: “What were the reasons for the formation of the coup of August 19 and what effects did it have on Iranian society?” It is based on the following: regaining access to oil and restoring the flow of oil to the West, overthrowing the national government of Mossadegh, restoring the Shah's credibility and power and establishing royal tyranny, restoring the power and dominance of British and American colonialism, etc. Among the causes of the occurrence and destruction of the oil nationalization movement, the beginning of a new era of dictatorship and tyranny in Iran became a turning point in the expansion of foreign influence and their direct presence in the country.