Morgannwg may refer to:
- Glamorgan, a historic county in south Wales, called in Welsh
- Kingdom of Morgannwg, a medieval kingdom in the same area
- Morgannwg (journal), the journal of the Glamorgan History Society
- Iolo Morganwg (1747–1826), a Welsh antiquarian and poet
See also
- Coleg Morgannwg, a former further education college in Rhondda Cynon Taf
- Glamorgan (disambiguation)