Château d'Agassac, Medieval fortress and winery in Ludon-Médoc, France.

Château d'Agassac is a wine estate in Ludon-Médoc whose castle stands behind a low green hedge. Its right section is a rectangular building with a steep dark grey roof, three white doors and three white-framed windows. To the left are two round towers with tall dark grey conical roofs and narrow windows, and a smaller round tower with a matching conical roof stands at the far right corner; all are pale beige stone.

The first known lord was Guillaume-Raymond d'Agassac in 1172; from 1238 the Gaillard de Gassac family held the seigniory, spanning 800 hectares. In 1357 it passed to the Albret family, and from 1580 to 1841 the Pommiers family owned it, one member serving as President of the Guyenne Parliament. In 1650 the Duke of Épernon's troops ravaged the Haut-Médoc and the castle needed repairs. Marcel Richier bought the estate in 1841, and Groupama acquired it in 1996.

The name Agassac comes from the Gaillard de Gassac family, lords of the seigneury from 1238. The estate's second wines carry the name Pomiès-Agassac, recalling the Pommiers family that owned it from 1580 to 1841. Since 2006 a second label, L'Agassant d'Agassac, has been made from 90% Merlot.

The estate is open for visits and wine tasting, and it can be rented for seminars, dinners or weddings. It belongs to the Great Wine Capitals Global Network and won the Best Of Wine Tourism contest in 2006, 2007, 2009 and 2012. It lies in the southern part of Ludon-Médoc, about 15 minutes north of Bordeaux.

The estate's wine was named one of the 100 best wines of the world by Wine Spectator in April 2003. The château and its old cellars were listed as monuments historiques in 2013.