Freedom of contract is recognized as a foundational pillar of private law in Iran. However, the limitations imposed by legislation and judicial practice in order to safeguard public order, good morals, and the rights of contracting parties often lack a coherent philosophical justification. This deficiency may lead to discretionary interpretations and inconsistencies in judicial practice. Adopting an interdisciplinary approach, this article seeks to analyze and justify the limitations on freedom of contract in Iranian law through the lens of Joseph Raz’s theory of authority and autonomy. The principal research question is how the limitations on freedom of contract in Iranian law can be philosophically and legally justified on the basis of Raz’s theory of authority and autonomy. The subsidiary question examines whether the existing statutory and judicial limitations in Iran are consistent with the principles of legitimate authority and autonomy articulated by Raz, and how such consistency may be strengthened. The central hypothesis of the study is that many of the current limitations on contractual freedom in Iranian law lack a coherent philosophical foundation. It is further hypothesized that Raz’s theory provides a structured normative framework capable of justifying legitimate restrictions while reconciling party autonomy with mandatory legal rules. The research adopts a descriptive–analytical methodology, encompassing the examination of legal texts, analysis of Iranian judicial decisions, and their comparative assessment in light of Raz’s philosophical account of authority and autonomy. The originality of the study lies in its direct engagement with the statutory and judicial constraints on contractual freedom through the theoretical framework of Raz’s conception of authority and autonomy. It proposes a coherent philosophical–legal model for justifying contractual limitations in Iranian law and designs an applied framework aimed at harmonizing party autonomy, mandatory rules, and public order. This framework may serve as a guide for future legislative reforms and judicial development. The findings suggest that embracing such a philosophical–legal framework would enhance the legitimacy of contractual limitations, reduce interpretive divergence and judicial inconsistency, and contribute to the systematic development of Iranian private law.