San Jose, officially the City of San José (/ˌsæn hoʊˈzeɪ, -ˈseɪ/ ^ⓘ SAN hoh-ZAY, -⁠SAY; Spanish: [saŋ xoˈse]), is a cultural, commercial, and political center within the San Francisco Bay Area and Silicon Valley. With a city population of 997,368 and a metropolitan area population of 1.95 million, it is the most populous city in both the Bay Area and Northern California and the 12th-most populous in the United States. Located in the center of the Santa Clara Valley on the southern shore of San Francisco Bay, San Jose covers an area of 179.97 sq mi (466.1 km²) and is the county seat of Santa Clara County.

Before the arrival of the Spanish, the area around San Jose was long inhabited by the Tamien nation of the Ohlone people. San Jose was founded on November 29, 1777, as the Pueblo de San José de Guadalupe, the first city founded in the Californias. It became a part of Mexico in 1821 after the Mexican War of Independence. Following the U.S. Conquest of California during the Mexican–American War, the territory was ceded to the United States in 1848. After California achieved statehood two years later, San Jose served as the state's first capital. San Jose experienced an economic boom after World War II, with a rapid population growth and aggressive annexation of nearby communities in the 1950s and 1960s. The rapid growth of the technology industry in Silicon Valley further accelerated the city's transition from an agricultural center to an urbanized metropolitan area, prompting Mayor Tom McEnery to adopt San Jose's current motto, "Capital of Silicon Valley", in 1988. Results of the 1990 U.S. census indicated that San Jose had surpassed San Francisco in population. By the early 2000s, San Jose was California's fastest-growing economy.

Today, San Jose is notable for its innovation, cultural diversity, affluence, and sunny and mild Mediterranean climate. Major companies including Cisco, eBay, Adobe, PayPal, NetApp, Cadence, and Zoom maintain their headquarters in San Jose. One of the wealthiest major cities in the world, San Jose was ranked in 2017 as having the third-highest GDP per capita (after Zurich and Oslo) and the fifth-most expensive housing market. It is home to one of the world's largest overseas Vietnamese populations, a Hispanic community that makes up over 30% of the city's residents, historic ethnic enclaves such as Japantown and Little Portugal, and the largest Sikh Gurdwara outside of India.

Educational and cultural institutions in San Jose include San Jose State University, Children's Discovery Museum of San Jose, the Tech Interactive, the San Jose Museum of Art, Winchester Mystery House, the Japanese American Museum of San Jose, Movimiento de Arte y Cultura Latino Americana, the Viet Museum, Rosicrucian Egyptian Museum, Hayes Mansion, Lick Observatory, San Jose Municipal Rose Garden, and the San Jose Center for the Performing Arts. Two major league sports teams, the San Jose Earthquakes and the San Jose Sharks, play their home games in San Jose. San Jose International Airport is the third-busiest airport in Northern California. VTA's rail and bus networks, together with Amtrak, ACE, BART, and Caltrain services, connect San Jose to the broader region through hubs such as Diridon Station.

San Jose is named after el Pueblo de San José de Guadalupe (Spanish for 'the Town of Saint Joseph of Guadalupe'), the city's predecessor, which was eventually located in the area of what is now the Plaza de César Chávez. In the 19th century, print publications used the spelling "San José" for both the city and its eponymous township. On December 11, 1943, the United States Board on Geographic Names ruled that the city's name should be spelled "San Jose" based on local usage and the formal incorporated name.

In the 1960s and 1970s, some residents and officials advocated for returning to the original spelling of "San José", with the acute accent on the "e", to acknowledge the city's Mexican origin and Mexican-American population. On June 2, 1969, the city adopted a flag designed by historian Clyde Arbuckle that prominently featured the inscription "SAN JOSÉ, CALIFORNIA". On June 16, 1970, San Jose State College officially adopted "San José" as the city's name, including in the college's own name. On August 20, 1974, the San Jose City Council approved a proposal by Catherine Linquist to rename the city "San José" but reversed itself a week later under pressure from residents concerned with the cost of changing typewriters, documents, and signs. On April 3, 1979, the city council once again adopted "San José" as the spelling of the city name on the city seal, official stationery, office titles and department names. As late as 2010, the 1965 city charter stated the name of the municipal corporation as City of San Jose, without the accent mark, but later editions have added the accent mark.

By convention, the spelling San José is only used when the name is spelled in mixed upper- and lowercase letters, but not when the name is spelled only in uppercase letters, as on the city logo. The accent reflects the Spanish version of the name, and the dropping of accents in all-capital writing was once typical in Spanish. While San José is commonly spelled both with and without the acute accent over the "e", the city's official guidelines indicate that it should be spelled with the accent most of the time and sets forth narrow exceptions, such as when the spelling is in URLs, when the name appears in all-capital letters, when the name is used on social media sites where the diacritical mark does not render properly, and where San Jose is part of the proper name of another organization or business, such as San Jose Chamber of Commerce, that has chosen not to use the accent-marked name.

San Jose, along with most of the Santa Clara Valley, has been home to the Tamien tribe of the Ohlone people since around 4,000 BC. The Tamien spoke Tamyen language of the Ohlone language family.