The Glamorgan flag is the flag of the county of Glamorgan. It was registered with the Flag Institute on 24 September 2013.
he flag is a banner of the arms of Iestyn ap Gwrgant, the last ruler of the Kingdom of Morgannwg, the predecessor of the county of Glamorgan. The design of three silver chevronels on a red field features in the coats of arms of many of the councils in the area, including those of Mid Glamorgan, South Glamorgan, West Glamorgan, and the Vale of Glamorgan. It also features on the flag of Cardiff where a dragon is holding the banner aloft symbolising Cardiff's status as county town of Glamorgan.