According to Allamah, the outward meaning of the Qur’anic verses is authoritative, and through the principle of interpreting the Qur’ān by the Qur’ān, all verses of the Qur’ān are considered clear and unambiguous (muḥkam).This study aims to extract and elucidate the foundational principles of the philosophy of language in the thought of Allamah Tabatabai and analyze their implications for Quranic exegesis. The research method is descriptive-analytical, with an approach that reconstructs Allamah's views in the three domains of philosophy, "conventional constructs" (i‘tibāriyyāt), and exegesis. The findings indicate that by integrating two key theories—“Signification” (dalālah) as the mechanism of meaning-making and “conventional constructs” (i‘tibāriyyāt) as the ontological-social foundation of language—Allamah arrived at a realist philosophy of language. In this framework, language is considered a constructed, yet reality-representing, bridge between the human mind and the objective world. The language of the Quran, utilizing the conventional-referential structure of human language and due to its divine origin, has perfected this structure to the utmost precision and efficacy, enabling it to refer to the most precise referents and existential truths. Furthermore, this philosophy of language provides the theoretical foundation for the method of "intra-Quranic exegesis" (tafsīr al-Qur'ān bi al-Qur'ān) in ‘Tafsīr al-Mīzān’ and serves as a criterion for mediating between the apparent and inner meanings, rejecting arbitrary allegorical interpretation (ta'wīl), and avoiding extreme relativism in understanding the Quran.