Fakhr al-Din Mustawfi (died 1290) was a Persian statesman from the Mustawfi family of Qazvin, who lived during the early Ilkhanate era. He was the elder cousin of the distinguished historian and geographer Hamdallah Mustawfi.^[1]

According to Hamdallah Mustawfi, Fakhr al-Din Mustawfi enjoyed a flourishing career under the Ilkhanate—first as the ṣāḥib(-i) diwān (finance minister, vizier) of Gaykhatu during his governorship of Anatolia, and then later as bureaucrat under the Ilkhan Arghun Khan (r. 1284–1291).^[1] He played a role in the downfall of the Ilkhanate ṣāḥib diwān Shams al-Din Juvayni, being part of the circle of advisors around Arghun, who urged him to make Shams al-Din stand trial, on the accusation of poisoning Arghun's father Abaqa Khan (r. 1265–1282).^[2] On 16 October 1284, Shams al-Din was executed, with Fakhr al-Din gaining his previous post of ṣāḥib diwān.^[3]

Two years later (1286), however, he was replaced by Jalal al-Din Simnani and sent to govern Anatolia.^[3] In the same year, Fakhr al-Din instigated the execution of Shams al-Din's son Sharaf al-Din Harun Juvayni through hateful slander.^[4] Fakhr al-Din strengthened Shams al-Din's policy of increasing the Iranian influence in Anatolia, appointing "innumerable Tabrizis, Hamadanis, Iraqis, Khushkanis, Khurasanis, Georgians, Alans, Marandis, Nakhjawanis, Tiflisis and Arranis." This led to a closer connection between Anatolia and the Iranian intellectual and literary world.^[5]

Fakhr al-Din Mustawfi eventually fell out and favour and was executed in 1290. The instigator behind this was the new ṣāḥib diwān Sa'ad al-Dawla, who achieved this through the spread of defamation. This earned him the animosity of the Mustawfi family.^[6][7]