Trewern is a village in Powys, Wales.
Trewern may also refer to:
- Trewern Hall or Trewern Farmhouse, a country house in Montgomeryshire, Wales
- Trewern House, one of the Grade II* listed buildings in Powys, Wales
- Trewern Mansion, in the village Llanddewi Velfrey, Pembrokeshire, Wales