Château de Chazay, Medieval castle in Chazay-d'Azergues, France.

The Château de Chazay is a former fortified castle in Chazay-d'Azergues, northwest of Lyon. Its surviving high logis is flanked by four corner towers and a tall polygonal stair turret, with a châtelet of two towers and a barbican guarding the entrance. Most of the buildings date from the 15th and 16th centuries, though parts may be Romanesque.

In the mid-9th century the King of Burgundy, Boson, gave the land of Chazay to the Abbey of Ainay, whose abbots installed a small convent; around 930 Abbot Raynal I became lord of Chazay. After a Hungarian raid around 934 the abbots fortified the site, and in 1173 a treaty placed Chazay under the archbishops of Lyon. Abbot Theodore du Terrail, uncle of the knight Bayard, rebuilt the castle between 1455 and 1505, and Philibert de Naturel completed its fitting-out from 1507. The sculpted 15th-century door and fireplace were classified on 4 June 1923.

The name Chazay comes from the castle, which gave its name to the commune. The 15th-century carved door on the ground floor and the fireplace on the first floor were classified as monuments historiques by decree of 4 June 1923. The Magat tower and the remains of the Benedictine priory church are also protected, inscribed on 6 January 1938.

The castle stands at the entrance to the Azergues valley, northwest of Lyon. Three successive wall circuits once enclosed it; today only the Porte du Castellum on Place de la Poste, the Porte du Baboin and a truncated tower near the present church remain, so a walk through the bourg traces the former defences.

The Magat tower and the remains of the Benedictine priory church were listed separately on 6 January 1938, within a perimeter bounded by Place de la Poste, Impasse Paradis, Rue des Porteries and Rue du Grand-Four. Of the three successive walls, only the Porte du Castellum on Place de la Poste, the Porte du Baboin and a truncated tower near the present church survive.