The Mountain Winery, formerly the Paul Masson Mountain Winery, is a winery in Saratoga, California, USA. It was founded by Paul Masson, a pioneer of the California wine industry. The winery became famous for its slogan, voiced by Orson Welles in television commercials, "We will sell no wine before its time."

Masson originally worked for Charles Lefranc, one of a number of French immigrants who had expanded the viticulture introduced into the Santa Clara Valley by the Catholic mission (Spanish missions in California) fathers. After Lefrancs death in 1887, Masson had a short-lived partnership with Lefrancs son Henry. Masson bought out Henrys share in the Almaden Vineyards and in 1892 Massons first sparkling wine was introduced at Almaden, and he eventually became known as the "Champagne King of California."

Masson purchased the Saratoga property in 1901. He later centered his champagne production here in Saratoga while other wines were developed at the Almaden operation.

In 1905, on a knoll above the winery, Masson built his house, dubbed "The Chateau," where he developed a reputation as an unrivaled host. His wife Louise Masson was a prohibitionist and did not attend the lavish dinner parties held at The Chateau. Masson was able to weather the strains Prohibition placed on the wine industry by selling grapes to the wholesale market and by receiving a special dispensation to sell sacramental wines.

The sandstone winery was rebuilt after the 1906 San Francisco earthquake, making use of sandstone blocks from the Saratoga Wine Companys building on Big Basin Way, also destroyed in the great quake. At this same time the ancient entrance portal from St. Patricks Church (Saint Patrick Proto-Cathedral Parish) in San Jose (San Jose, California), which was also destroyed in the quake, was added to the structure.

Wine making ceased in 1952, and the concert series began in 1958. These concerts featured famous performers such as Ella Fitzgerald, Tony Bennett, Aimee Mann, Ringo Starr, Stevie Wonder, Ray Charles, The Beach Boys, and Carlos Santana.

New owners purchased the winery and planted new vineyards in 2004. Grapes from the 2006 harvest will be used to produce the first new Masson wines.

The winery is a California Historical Landmark (#733) and is listed on the National Register of Historic Places.