Mohammed Arkoun (1928–2010) was a contemporary thinker in the Islamic world and a figure within the movement of Islamic religious reformist thought whose intellectual project was grounded in a critique of Islamic reason and a critical rethinking of the religious heritage. One of the central concepts in his thought is the “Unthought,” which refers to domains of knowledge and historical experience that have been excluded from the realm of legitimate thought in the course of the formation of official and dominant discourses. The present study aims to examine the role of this concept in rethinking religious tradition and to elucidate its cultural implications within the framework of Arkoun’s project of critiquing Islamic reason. The main research question is how the “Unthought” makes possible a critical re-reading of religious tradition and what analytical potential it offers for understanding cultural transformations in Islamic societies. The study adopts a descriptive-analytical approach and employs textual and conceptual analysis based on Arkoun’s primary works.