Every historical account is influenced by the historian's perspective and attitude. The assumptions that a historian has are the most significant factors that determine the history he/she writes. The same goes for the history of Islamic architecture. The historian of architecture deals with his/her subject depending on his/her understanding of history and architecture. For example, if a historian has an evolutionary and progressive view of history, he/she gets a special narrative of architectural history. In the same way, whether the historian considers architecture as an objective or subjective phenomenon, what methods he/she considers knowing it, how evaluates it and with what criteria, and even how he presents the knowledge he/she has obtained, all guide the historical account. The study of Islamic art and architecture was shaped by Orientalism. Subsequently, scholars from other disciplines such as archaeology and art history also began studying Islamic art and architecture. Still, many of their studies continued to be based on the same assumptions, concepts, and terms developed by the Orientalists. This research aims to identify the philosophy of the history of Islamic architecture from the Orientalist view and to address the question of how it has influenced the field. Oriental historiography of Islamic architecture indicates what assumptions of the philosophy of history? This research is qualitative, and its method is descriptive and analytical. Since this research belongs to the field of philosophy of science and seeks to know the assumptions of the history of Islamic architecture as a field of knowledge, it has benefited from logical reasoning.According to the study, the four main components of the Philosophy of history are historical reality, historical objectivity, value in history, and historical explanation. Thus, the sub-questions of the research are: In the oriental historiography of Islamic architecture, what is the reality of Islamic architecture? How can it be recognized? What are the selections and evaluations of orientalists about Islamic architecture? And how do they explain Islamic architecture? The answers to these questions clarify the philosophy of history in Orientalism. Based on the study, it can be said that in Orientalism Islamic architecture is defined as the "Other" of Western architecture and it lacks history; such a view has led to the formation of an attitude that portrays Islamic architecture as a stagnant subject belonging to the past and as a result identify it in opposition to modern architecture. In addition, Orientalism identifies Islamic architecture as a unified essence that has no relationship with its time and context. Therefore, any diversity, multiplicity, and temporality are ignored in this field. In terms of historical objectivity, it can be said that Orientalism looks at Islamic art and architecture with a positivist and materialistic approach. So Islamic architecture is like an independent object that exists in the outside world and with positivist approaches and modern rationality, a complete understanding of it can be obtained. The selections and evaluations of orientalists from the history of Islamic architecture are also based on the Eurocentric discourse that considers Islamic art and architecture as romantic, decorative, and exotic phenomena; these features, in contrast to rationality and historicity, are introduced as the weakness of Islamic art and architecture.