Al-Malik al-Mansur Fakhr al-Din Uthman ibn Jaqmaq, more simply known as Al-Mansur Uthman (Arabic: المنصور فخر الدين عثمان بن جقمق) was Sultan of Cairo's Mamluk Burji dynasty (1453).
His father named him Uthman after the House of Osman to celebrate the Ottoman victory against the European Christians at the Battle of Varna.
Inal al-Ajrud group and the Mamluks house Barquq occupied Kalat al-Djabal (Fortress of the Mount).
He was nominated as Sultan by the Abbasid Caliph of Cairo and four kadis with the title of Al-Malik al-Mansur Fakhr al-Din.
He later returned to Cairo during the rule of Qaitbay who was a Mamluk to his father, Jaqmaq.