Chittagong Division (Bengali: চট্টগ্রাম বিভাগ), officially Chattogram Division, is geographically the largest of the eight administrative Divisions of Bangladesh. It covers the southeasternmost areas of the country, with a total area of 34,529.97 km (13,332.10 sq mi) and a population according to the 2022 census of 33,202,326, which made it the second most populous division of Bangladesh and the 45th most populous subnational entity in the world — more populous than all but 43 other countries. However, this changed in 2024 with the Division being split in two by the creation of a separate Cumilla Division, and the reduced administrative division includes mainland Chittagong District, neighbouring districts and the Chittagong Hill Tracts.
Chittagong Division is home to Cox's Bazar, the longest natural sea beach in the world; as well as St. Martin's Island, Bangladesh's sole coral reef.