Carcassonne Cathedral (Cathédrale Saint-Michel de Carcassonne) is a cathedral and designated national monument in Carcassonne, France. It is the seat of the Roman Catholic Bishop of Carcassonne.

The building was built in the thirteenth-century as a parish church, dedicated to Saint Michael. Following war damage in the fourteenth century it was subsequently rebuilt as a fortified church.

In 1803 St Michael's was elevated to cathedral status, replacing the pre-Revolutionary cathedral dedicated to Saints Nazarius and Celsus. The old cathedral now serves as the Basilica of St. Nazaire and St. Celse.