Seandún GAA is a Gaelic Athletic Association division in Cork, Ireland. The division, one of eight affiliated to the Cork County Board, organises its own junior grade competitions in both hurling and Gaelic football.

Centred around Cork city and it's wider hinterland, Seandún GAA Division was founded on 1 April 1925. The division derives its name from Shandon, whose bells are a symbol of Cork city and form part of the division's crest. Seandún was one of a number of divisions established around that time in an effort to improve the administrative organisation of the GAA in Cork and to provide competitions for the ever-increasing number of clubs, particularly at junior level. Respective competitions in both hurling and Gaelic football were organised in 1926, with College Rovers becoming the inaugural winner of the City JHC and Geraldines claiming the City JFC.

Seandún fielded a hurling team in the Cork SHC for the first time in 1934. The team was composed of players from junior and intermediate clubs in the division and reached the semi-finals. Seandún has reached six semi-finals in total but has never contested a final. Seandún has also fielded a Gaelic football team in the Cork SFC. The division's only semi-final appearance ended with a defeat by Clonakilty in 1968.

Further B-grade and C-grade competitions in both hurling and Gaelic football were created by the Seandún Board over time. The Seandún divisional teams' participation in the respective Cork SHC and SFC has been sporadic in recent times.