Duke of Fronsac (French: duc de Fronsac) was a title of French nobility, first created by promoting the seigneurie of Fronsac to a duchy in 1608, but the title became extinct a few decades later. This title was revived in 1634 for Armand Jean du Plessis de Richelieu, better known as Cardinal Richelieu, and it survived until the 19th century.