The main objective of the research is to examine the impact of Sharia on the legislative process in Iran and Egypt, with a teleological and Ijtihad-based approach of the Guardian Council. The research method is descriptive-analytical, and the data have been collected through the analysis of laws and legislative processes in Iran and Egypt. The findings indicate that in both countries, Islamic Sharia is used as the primary source of legislation; however, the teleological and Ijtihad-based interpretation of Sharia faces challenges such as differences in the interpretation of Sharia objectives, conflicts with modern requirements, and practical implementation issues. In Iran, the Guardian Council performs these interpretations, while in Egypt, the Dar al-Ifta and the Islamic Fiqh Assembly do so. Additionally, textualist interpretation trends have, in some cases, particularly in the interpretation of Article 64 of the Iranian Constitution, led to new challenges. Therefore, constitutional interpretation without clear and precise guidelines or based on transient interests should be avoided. Article 2 of Egypt’s 2014 Constitution also outlines the limitation of Islam’s role in governance, considering only definitive Islamic rulings for the adaptation of valid laws. The results of the research suggest that for aligning laws with Sharia principles and social needs, it is essential that the Sharia oversight of the Guardian Council be conducted in an Ijtihad-based manner, considering the intentions of the constitutional framers and public interests.