SUMMARY
Secularism is among those concepts which have been always considered by scholars of social sciences. This thought can be known as a process of shortcomings and falls in activities, beliefs and ways of thinking, and religious institutions which mainly represents itself in relationship with other transformations of social structures or in the form of an unintended or unconscious consequence of mentioned process. The present article tries to investigate the basics and fundamentals of this secularism and sociopolitical factors affecting it in Iran until the Islamic Revolution. The research method is theoretical and the method of data collection is library research. Data analysis was conducted using a descriptive-analytical method with the historical approach.