Khan Jahan Ali (Uzbek: Jahonali Khon) d. ca. October 25, 1459, also known as Ulugh Khan and Khan-i-Azam, was an Muslim Sufi Saint and local ruler in Bagerhat (now in Bangladesh). The official title Khan-i-Azam signifies that he was an officer of the Bengal Sultan Nasiruddin Mahmud Shah I (1437– 1459). The word Ulugh before his name speaks of his Uzbek origin. It is believed that he built the great Shait Gumbuj Mosque.
Khan Jahan, a noble under the Tughlaqs, seems to have come to Bengal just after the sack of Delhi (1398) by Timur. He acquired the forest area of the Sundarbans asjagir (fief) from the sultan of Delhi and subsequently from the sultan of Bengal. He cleared up the dense forest in the Sundarban area to set up human settlements.
He ruled over an area called Khalifatabad stretching up to Naldi to the north of Narail.
He founded some townships, built mosques, madrasahs and sarais, roads, highways and bridges, excavated a large number of dighis in the districts of greater Jessore and Khulna, that comprises the Mosque city of Bagerhat. Besides in his fortified metropolis of Khalifatabad (modern Bagerhat) he built three townships, such as Maruli Kasba, Paigram Kasba and Bara Bazar. He is said to have built a highway from Bagerhat to Chittagong, a 32-kilometre (20 mi) long road from Samantasena to Badhkhali, and a road running from Shuvabara to Daulatpur in Khulna. The most notable of his architectural monuments are Shatgumbaj Mosque or the Sixty Dome Mosque at Bagerhat, Masjidkur Mosque and a single-domed mosque attached to his tomb. Of the large number of dighis and ponds excavated by him the most notable are the Khanjali Dighi (1450) near his tomb and Ghoradighi, measuring 230 by 460 metres (750 by 1,500 ft) to the west of Shatgumbaj Mosque. Khan Jahan introduced a new architectural style in his buildings, which is named after him. The Khan Jahan style is seen in a group of buildings in the greater districts of Khulna, Jessore and Barisal.
Khan Jahan died on 25 October 1459 (27 Dhul Hijjah 863 AH).
A proposed airport in Mongla, Bagerhat is being named after him.