Firhouse (Irish: Teach an Giúise) is an outer suburb of Dublin, in the county of South Dublin, in the south of the traditional County Dublin, Ireland. It developed from a rural village by the River Dodder, with a second settlement, Upper Fir-house, nearby. It is just outside the M50 orbital motorway, and in the postal district of Dublin 24 (Eircode routing key D24). It is adjacent to Knocklyon (with which it shares a townland) and Ballycullen, and close to Tallaght. In the historic divisions of local administration, Firhouse is in the civil parish of Tallaght and the barony of Uppercross.