Temecula Valley is an American Viticultural Area (AVA) within the Temecula Valley landform, located in southwestern Riverside County, California nestled along the eastern slopes of the Santa Ana Mountains. It was initially established on October 22, 1984, as the nation's 69th, the state's 42nd and the county's initial AVA by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), Treasury as "Temecula" after reviewing petitions submitted by the Rancho California/Temecula Winegrowers Association and Callaway Vineyard and Winery, Temecula, California in 1981. The petitioners inititally proposed to establish a viticultural area in Riverside County to be named "Temecula," "Murrieta," and "Rancho California" but the ATF did not adopt it.
In 2004, it was renamed "Temecula Valley" by the Alcohol and Tobacco Tax and Trade Bureau (TTB), approving the 2001 petition submitted by the Temecula Valley Winegrowers Association. The petition stated the name change would provide a more accurate description of the Temecula geography and greater clarity as to its location for wine consumers and the public. The petition did not request any change to the established AVA boundaries. This was the first AVA to change its name after the initial approval.
Temecula Valley encompasses 33,000 acres (52 sq mi) with 5,000 acres (8 sq mi) is located in a "protected" area referred to as the Citrus/Vineyard Zone. This area is generally located in and around the Rancho California Road area within Riverside County. County guidelines strictly enforce the number of acres needed to build a winery, lodging and other limited housing and commercial ventures.

Both the name and the history of Temecula dates back hundreds of years, to the indigenous Luiseno Indians who called themselves "Temeku", or in anglicized form "Temecula" (/təˈmɛk.jə.lə/ ^ⓘ tuh-MEH-kyoo-luh). This word may be roughly translated as "place where the sun breaks through the white mist." The term “Luiseño” dates back to the Spanish period (1797–1834), and was used to describe their enslavement to the Mission San Luis Rey.

The Pechanga Band of Natives call themselves Payómkawichum (the People of the West). Temecula's viticultural area, near the streets of Los Nogales Camino Del Vino, was identified as the site of the Temecula Massacre, where the Payómkawichum were ambushed and attacked by a group of Californios and Cahuilla natives in January 1846. The death count was estimated around 30 to 100.

Tensions remained high between Temecula Natives and settlers throughout the 19th century. In December 1875, a group of settlers banded together and forcibly removed the Payómkawichum from the area. They were left with little to none of their belongings and stranded a few miles south of the town site. Later, President Chester A. Arthur issued an Executive Order on June 27, 1882, and created the Pechanga Reservation.

The original Temecula petition stated that this description applied to the entire viticultural area, which is in a valley characterized by bright sun and misty marine air that flows inland from the Pacific Ocean. The 1984 decision noted that it is this marine air, which enters the Temecula Valley through gaps in the Santa Ana Mountains, that allows grape growing in this area. Franciscan priests from the early Alta California missions recorded visiting the Indians as early as October 1797. They later built an "Asistencia" near the village site of the Temekus, just south of where Murrieta Creek empties into the Temecula River, currently known as Temecula Canyon. As the name suggests, the "Asistencia" assisted the nearby Mission San Luis Rey in its work and provided lodging for traveling priests.

Temecula's viticultural history dates back to the mid-nineteenth century, if not earlier. Evidence of that fact is found in the records of Land Case Number 55, Southern District of California. In 1843, the Mission San Luis Rey granted Pablo Apis, one of its workers, one-half league, about 2,000 acres, of Temecula Rancho with "150 stocks of vines." This area is known today as "Little Temecula." The large planting suggests the Temecula vineyards in earlier times supplied wine to the Mission. The land was recognized for its viticultural purpose when purchased in 1846 by a French-born Californian Jean-Louis Vignes, a recognized vintner and ranchero in Pueblo de Los Ángeles. During the previous decade, Vignes has written to his relatives in France to persuade them and other "intelligent countrymen" to join in the development of California's wine trade At least eight of Vignes' relatives emigrated and it is likely Vignes selected Temecula Land Grant as prime vineyard land.

There is little official documentation of grape growing in Temecula during the latter half of the nineteenth century. However, promotion of the region as suitable for vines was widespread. The 1890 publication, "An Illustrated History of Southern California," described Temecula as 100 sq mi (64,000 acres) of valley lands and undulating hills. "The soil is adapted to a diversified agriculture: fruit and vine growing will be largely undertaken in the future."

Vineyards still were not flourishing in 1909 when Frank McDonald wrote "Thriving, Tempting Temecula." He records only one vineyard (no acreage indicated) of Zinfindel and Mission grapes one mile north of Temecula. Temecula's first real viticultural boom began with the advent of Prohibition in 1920. As the prices of grapes soared, most if not all Temecula's farmers took to planting grapes, although not in conspicuous acreage. Names like Escallier, Borel, Cazas, Domino and others to this day are recognized by old-time Temecula residents as grape growers of the 1920s and 1930s. Their vineyards were scattered throughout the current viticultural area.