Llanddew is a small village about 2 km or 1 mile north-east of Brecon, Powys, Wales. within the community of Llanddew.
Its manor belongs to the bishops of Saint David's, who formerly had a residence or bishop's palace there, of which some ruins still remain. These incorporate a double-sided vaulted well, known as Bishop Gower's Well.
St David's parish church in Llanddew is the oldest church in the historic county of Brecknockshire. The building dates from around the 13th century and has a cruciform shape, with a central tower. At one time, there were monastic buildings at the church, and the monks would go around the local area preaching and giving communion.