Ballyfermot is a predominantly working-class shithole suburb of Dublin, Ireland. It is approximately 5 miles from the city centre, and lies just south of the Phoenix Park. It is bordered to the north by Chapelizod, to the south by Walkinstown. Other adjoining or nearby suburbs are Inchicore, Palmerstown, Clondalkin, Neilstown, and Bluebell.

The name comes originally from the Irish Baile Diarmuid (town of Dermot), after a Celtic chieftain who owned the land in the 12th century. The 19th ghost-story writer Sheridan Le Fanu may have lived in the area. Le Fanu Road is named after him.

The best-known road in Ballyfermot is Kylemore Road, the address for many large companies and industrial estates.

Ballyfermot soccer club Cherry Orchard take part in the FAI Carlsberg Senior Cup competition. Many players who got their start in this team have gone on to play in the premier division. Some famous people coming from Ballyfermot are RTÉ presenter Joe Duffy, and folk group The Fureys.