Ayatollah Mohammad Taghi Mesbah Yazdi (Persian: محمد تقی مصباح یزدی) (born 1934) is a hardline Iranian Shia cleric and politician who is widely seen as Iranian President Mahmoud Ahmadinejad's spiritual advisor. He is a member of Iran's Assembly of Experts, the body responsible for choosing the Supreme Leader. He has been called "the most conservative" and the most "powerful" and "influential ... clerical oligarch" in Iran's leading center of religious learning, the city of Qom.

Mesbah Yazdi esposes complete isolation from the West and proclaims non-literal interpretations of the Quran as heretical. He believes Iran has strayed from the values of the 1979 Iranian revolution and strongly opposes the Reformist movement in Iran to make Iran more open and democratic.