Merlot ( MUR-loh) is a dark blue–colored wine grape variety, that is used as both a blending grape and for varietal wines. The name Merlot is thought to be a diminutive of merle, the French name for the blackbird, probably a reference to the color of the grape. Its softness and "fleshiness," combined with its earlier ripening, make Merlot a popular grape for blending with the sterner, later-ripening Cabernet Sauvignon, which tends to be higher in tannin.

Along with Cabernet Sauvignon, Cabernet Franc, Malbec and Petit Verdot, Merlot is one of the primary grapes used in Bordeaux wine, and it is the most widely planted grape in the Bordeaux wine regions. Merlot is also one of the most popular red wine varietals in many markets. This flexibility has helped to make it one of the world's most planted grape varieties. As of 2004, Merlot was estimated to be the third most grown variety at 260,000 hectares (640,000 acres) globally. The area planted to Merlot has continued to increase, with 266,000 hectares (660,000 acres) in 2015.

While Merlot is made across the globe, there tend to be two main styles. The "International style" favored by many New World wine regions tends to emphasize late harvesting to gain physiological ripeness and produce inky, purple colored wines that are full in body with high alcohol and lush, velvety tannins with intense, plum and blackberry fruit. While this international style is practiced by many Bordeaux wine producers, the traditional "Bordeaux style" of Merlot involves harvesting Merlot earlier. This maintains the acidity and produces more medium-bodied wines with moderate alcohol levels that have fresh, red fruit flavors (raspberries, strawberries) and potentially leafy, vegetal notes.