Mostowfi ol-Mamalek () was one of the positions and titles of the Iranian court from the Ilkhanate to the Qajar era.
Mostowfi ol-Mamalek was the leader of all Mostowfis. During the Safavid era, Mostowfi ol-Mamalek was in charge of the finances of the whole country and all the financial and tax affairs of the country and the dismissal and installation of the Mostowfis were done by him. Mostowfi ol-Mamalek was a powerful official during this period, and at the end of Soltan Hoseyn's reign they had the right to participate in the Supreme State Council.
After his coronation, Nader Shah divided the position of Mostowfi ol-Mamalek among four people and appointed each of them to be in charge of the finances of a part of the country. During Karim Khan Zand's rule, this position was again given to one person. At the beginning of the Qajar era, with the expansion of the Qajar bureaucracy, Mostowfi ol-Mamalek became the second prime minister after the Shah. One of the most influential political-noble families of Iran in the Qajar era named Mostowfian Ashtiani family took their name from this title.