Yousuf Khan Mostashar al-Dowleh (Persian: یوسف‌خان مستشارالدوله) (1823–1895) was an Iranian writer, intellectual and diplomat.

[1] He was eventually imprisoned for his views during the reign of Nasser al-Din Shah and died three years later.

[3] At the end of 1867, he was appointed as the Paris Chargé d'affaires, and according to his writings, he observed the Exposition Universelle and considered it "beautiful".

[4] Mostashar al-Dowleh completed the famous treatise "One Word" in Paris in the last months of his service there and showed it to Akhundov on the way back to Iran in 1870 in Tbilisi.

At that time, the Akhtar Istanbul newspaper published criticisms of the Iranian courts, and on the suspicion that he was involved in publishing those criticisms, he was accused and dismissed by the order of Nasser al-Din Shah and sentenced to five months in prison.