Château Marbuzet, formerly Château de Marbuzet, is a Bordeaux wine estate in the Saint-Estèphe appellation, which depends on the illustrious Château Cos d'Estournel, 2nd Grand Cru Classé and emblem of the Saint-Estèphe appellation.

Rather unknown, Château Marbuzet is located in the hamlet of Marbuzet itself on the heights of Saint Estèphe, its building in full view, adorned with a semicircular Corinthian colonnade. In the 18th century, the hamlet of Marbuzet was part of the property of Nicolas-Alexandre de Ségur, then owner of Château Latour, Lafite, Mouton, and Calon-Ségur. When he died in 1776, the estate was bought by Marc Antoine Domenger, manager of Latour, and then by the wine broker Jules Merman, who built the current château. The wines of Château de Marbuzet were then recognised and were awarded the classification of Grand Bourgeois Exceptional.

Until the 1994 vintage, the vineyard of Château Marbuzet was blended with the young vines of Château Cos d'Estournel and constituted the second wine of Cos. Since then, Château Marbuzet has become a full-fledged cru produced on the 7 hectares that surround the Château. The second wine of Cos d'Estournel is now "Les Pagodes de Cos".