Wine Country is a region of California, in the northern San Francisco Bay Area, known worldwide as a premier wine-growing region. The region is famed for its wineries, its cuisine, Michelin star restaurants, boutique hotels, luxury resorts, historic architecture, and culture. Viticulture and wine-making have been practiced in the region since the Spanish missionaries from Mission San Francisco Solano established the first vineyards in 1812.

There are over 1,700 wineries in the North Bay, mostly located in the area's valleys, including Napa Valley in Napa County, and the Sonoma Valley, Alexander Valley, Dry Creek Valley, Bennett Valley, and Russian River Valley in Sonoma County. Wine grapes are also grown at higher elevations, such as Atlas Peak and Mount Veeder AVAs. Cities and towns associated with the Wine Country include Santa Rosa, Healdsburg, Sonoma, Kenwood, Petaluma, Sebastopol, Guerneville, Windsor, Geyserville, and Cloverdale in Sonoma County; Napa, Yountville, Rutherford, St. Helena and Calistoga in Napa County; and Hopland and Ukiah in Mendocino County. Wine is also an important part of the economy in nearby Lake, Solano, and Yolo counties.

Wine Country is generally regarded as the combined counties of Napa, Sonoma, Mendocino, Lake, Solano, and western parts of Yolo County. These counties contain the following American Viticultural Areas (AVAs):

The six-county North Coast AVA overlaps with the Wine Country as defined here and also includes Marin County. In addition, the names of the counties themselves are legal for use as appellation names.

The earliest prehistory of the Wine Country involves habitation by several Native American tribes from approximately 8000 BC. The principal tribes living in this region included the Pomo, Coast Miwok, Wappo and Patwin, whose early peoples practiced certain forms of agriculture, but probably not involving the cultivation of grapes. During the Mexican Colonial period and after, European settlers brought in more intensive agriculture to the Wine Country, including growing grapes and wine production. Some of the historical events that led to the establishment of California as a state transpired in the Wine Country. In particular, the town of Sonoma is known as the birthplace of American California. Agoston Haraszthy is credited as one of the forefathers of the California wine industry in Sonoma by his planting of grapes in the lower Arroyo Seco Creek watershed of Sonoma County.

In 2017, many portions of California's Wine Country were heavily devastated by wildfires, including the October 2017 Northern California wildfires.

Founded in 1880, the UC Davis Department of Viticulture and Enology is the most famous and established school for research and education in winemaking in the Northern California region and the United States. It has contributed greatly to Northern California’s growth and establishment as a wine producing region.

A diversity of aquatic and terrestrial organisms populate the Wine Country and its riparian zones. Winter-run Chinook salmon (Oncorhynchus tsawytscha), Delta smelt (Hypomesus transpacificus) and steelhead (Oncorhynchus mykiss) are the most prominent fishes. Researchers have studied anadromous fish-movements extensively in Sonoma Creek and in the Napa River as well as in the Laguna de Santa Rosa - not only in the mainstems, but in many of the tributaries. These investigations have demonstrated a historical decline in spawning and habitat value for these species, primarily due to sedimentation and secondarily to removal of riparian vegetation since the 19th century.