Château de Dio-et-Valquières, Medieval castle in Dio-et-Valquières, France.

Château de Dio-et-Valquières is a medieval stronghold whose construction ran from the 11th to the 14th century, standing above the village of Dio-et-Valquières in the Hérault. Its tall square keep of rough grey-brown masonry has a flat top, a row of small arched corbels beneath the roofline and a metal scaffold frame at the highest point. Below it a lower building with a pale stone facade and a pitched roof adjoins a ruinous stone wall.

A Visigothic castrum was built on the hill in the 6th century under Theodoric I of Austrasia to guard the Orb river. Construction of the castle itself began in the 11th century under the Lords of Boussagues. The Fleury family later converted it into a residence, a transformation completed by Jean de Fleury in the 17th century. After the French Revolution it passed through several owners and fell into ruin; a ten-year restoration was carried out in the 21st century.

The historical monument displays an educational model showing the architectural transformations of the castle from the 12th and 17th centuries to present day.

The site has been open to visitors since its restoration in the 1990s, allowing exploration of its interior spaces and walkways. Sturdy footwear is advisable since stairs and pathways are uneven throughout the structure.

The castle is where the final fight between Jonathan Joestar and Dio Brando in JoJo's Bizarre Adventure: Phantom Blood takes place. The site's history reaches back to the 6th century, when Theodoric I of Austrasia had a castrum built on the mound to house troops and watch the Orb river.