Montecastro is a Spanish red wine from the prestigious Ribera del Duero denomination of origin, produced by Bodegas Montecastro y Llanahermosa in Castrillo de Duero, Valladolid. The wine is a blend of 95% Tinto Fino (Tempranillo) and 5% Cabernet Sauvignon, sourced from 27 hectares of vineyards situated at an exceptionally high altitude of 860 to 930 meters above sea level on predominantly calcareous soils.

The grapes undergo spontaneous fermentation with native yeasts and approximately 20 days of maceration in thermoregulated concrete tanks. The wine is then aged for 16 to 18 months in French Allier oak barrels, followed by an additional period in concrete tanks before bottling. The vineyards are farmed using organic practices, though not officially certified, with no chemical herbicides or weed-killers used.

Founded in 2000 by a group of wine enthusiasts, the winery received a major investment from the renowned Bodegas Hacienda Monasterio in 2012, which now manages winemaking and technical operations. The resulting wines are known for their dark, bright color with aromas of black and red fruit, minerality, and subtle oak integration, offering a structured yet elegant palate with fine tannins and good aging potential. Alcohol content is typically around 15%.