Mehmet Beg or Mehmet Bey of Karaman (Turkish: Karamanoğlu Mehmet Bey), also known as Shams al-Din Mehmed Beg was the third ruler of the Karamanids. Mehmet Fuat Köprülü suggested that the government officials, who had been educated under the influence of the Persian culture, had used the Persian language in their state"s official business, and this strong compulsory of using Persian as official language had lasted until the Karamanids lord Mehmed Bey"s invasion of Konya. According to Dilaçar, in his firman dated 13 May (15 May ?) 1277, he ordered that "from that day forward, in the council, in the dervish lodge, in the court, in the assembly, in the square, no language but Turkish should be spoken".
Before him, the Seljuq elite in Anatolia used Persian in literature and Arabic in government and science.
The Turkmen however could not understand these languages. After his failed rebellion in Ankara, he died in a conflict against Seljuq-Mongol troops.