Fiddaun Castle is a tower house in Tubber, County Galway, close to the border of County Clare in Ireland. It is a National Monument of Ireland.
== Name == Fiodh Duin means "wood of the fort" in Irish.
== Geography == Fiddaun Castle is situated between Lough Doo and Lough Aslaun near the modern village of Tubber.
== History == Fiddaun is a mid-16th century Irish tower house in the Kiltartan barony of the Uí Fiachrach Aidhne, one of four O'Shaughnessy castles. Fiddaun was most likely built by Sir Roger Gilla Dubh Ó Seachnasaigh, as he is the first mentioned living there and it is not known before his time.
== Today == This tower house is most noted for its well preserved inner bawn wall. It is located on private land and maintained by the Office of Public Works.