Muhammad Rida al-Muzaffar (Arabic: محمد رضا المظفر) (1904 - 1964) was a Shia Marja',[1] philosopher and jurist.

His book in Islamic sciences is Usul al-Fiqh or the principles of jurisprudence written according to the thought school of Agha Shaykh Muhammad Hosein Isfahani, one of the Shia Marja's.

Like many ulama, he participated in a variety of courses and scholarly circles, leading to the completion of his advanced education in religious seminaries.

According to the school of thought of his master, Muhammad Husein Isfahani, Muzaffar believes in new orderness on the subjects.

As a result, he divided subjects into four categories: alfaz, rational discussion (mabahith aqliyyah), hujjat, usul Amaliyyah (practical principles).