Ridge Vineyards is a California winery specializing in Cabernet Sauvignon, Zinfandel, and Chardonnay wines. Ridge produces wine at two winery locations in northern California. The original winery facilities are located at an elevation of 2,300 feet on Monte Bello Ridge in unincorporated Santa Clara County in the Santa Cruz Mountains AVA, south of Los Altos, California and west of Cupertino, California. The other Ridge winery facilities are at Lytton Springs in the Dry Creek Valley AVA of Sonoma County. Ridge Vineyard's 1971 Monte Bello Cabernet Sauvignon gained prominence for its fifth-place finish in the 1976 "Judgment of Paris" wine tasting.

Zinfandel is a variety of black-skinned wine grape. The variety is grown in over 10 percent of California vineyards. DNA analysis has revealed that it is genetically equivalent to the Croatian grapes Crljenak Kaštelanski and Tribidrag, as well as to the Primitivo variety traditionally grown in Apulia, Italy, where it was introduced in the 18th century, and Kratošija in Montenegro. The grape found its way to the United States in the mid-19th century, where it became known by variations of a name applied to a different grape, likely "Zierfandler" from Austria.