Wern-ddu farmhouse, Llantilio Pertholey, Monmouthshire is a farmhouse of 17th century origins. It has been significantly altered in the 18th, 19th and 20th centuries and the Monmouthshire antiquarian, Sir Joseph Bradney recorded that it had "suffered so much by continual alterations that it shows but little of its antiquity". It is a Grade II* listed building.