St. Augustine, a Christian philosopher and prolocutor, and Avicenna, a Muslim philosopher and theologian, are both prominent personalities in philosophy and theology. “ state Theory” is one of the key issues in political thought. Therefore, in this paper, we study and compare the issue from the viewpoints of the two philosophers in terms of the origin and nature of the government and its relation with conceptual, functional, and structural perspectives. Thus, the research question is: How can we conceptualize and compare Government Theory in Avicenna and St. Augustine’ s political philosophy in terms of the origin and nature (of the government)? To address and examine the question, it is hypothesized that in Augustine’ s viewpoint, the government is rooted in the human beings’ “ first sin” and rebellious nature, having a customary nature, and its only function is maintaining security and peace in society. According to Avicenna’ s theory, however, the government is originated in a divine and civil nature of human beings, being religious in nature, and its function is leading society towards the prosperity of this world and the salvation of the other world in an ideal way. The findings indicate that the starting point of each of the philosophers on human being’ s nature determines the nature of the government in terms of the customary or religious nature and functional or structural perspectives. Therefore, in Augustine’ s viewpoint, the government has an instrumental and mechanical approach; while, in Avicenna’ s political viewpoint, the government has an organic approach from the conceptual perspective. Furthermore, Augustine’ s theory is related to a realistic attitude, while, Avicenna’ s theory is related to an idealistic approach. The inquiry uses a descriptive-analytical method and as library-based research has been carried out through careful analysis and evaluation of the existing literature and research on the subject.