Californios (singular Californio) are Hispanic Californians, especially those descended from Spanish and Mexican settlers of the 17th through 19th centuries who arrived under Spanish and Mexican rule before California was annexed by the United States. California's Spanish-speaking community has resided there since 1683 and is made up of varying Spanish and Mexican origins, including Criollos, Mestizos, Indigenous Californian peoples, and small numbers of Mulatos. Alongside the Tejanos of Texas and Neomexicanos of New Mexico and Colorado, Californios are part of the larger Spanish-American/Mexican-American/Hispano community of the modern United States, which has inhabited what is now the American Southwest and the West Coast since the 16th century. Some may also identify as Chicanos, a term that came about in the 1960s.

The term Californio (historical, regional Spanish for 'Californian') was originally applied by and to the Spanish-speaking residents of Las Californias during the periods of Spanish California and Mexican California, between 1683 and 1848. The first Californios were the children of the early Spanish military expeditions into northern reaches of the Californias, which started out from what is now modern Mexico. Many of their fathers were soldiers who established the presidios of California and guarded the California mission system.

Later, the primary cultural focus of the Californio population became the Vaquero tradition practiced by the landed gentry, who received large land grants and created the Rancho system. In the 1820s–40s, American and European settlers increasingly migrated to Mexican California. Many married Californio women and became Mexican citizens, learning Spanish and often converting to Catholicism, the state religion. They are often also considered Californios, for their adherence to Californio language and culture.

In 2004 studies estimated that between 300,000 and 500,000 state inhabitants have ancestry from the Spanish and Mexican eras of California.

The term "Californio" has different meanings depending on the author or source. According to the Real Academia Española, a Californio is a person native to California. Merriam-Webster dictionary defines a Californio as both a native or resident of this state and a specific ethnic group: the Spanish settlers and their descendants in California.

Authors such as Douglas Monroy, Damian Bacich or Covadonga Lamar Prieto, among others, define Californios as exclusively applying to Alta California residents and their descendants.  

Historians Hunt Janin and Ursula Carlson consider a Californio to be any settler who migrated to Alta California and their descendants; and also non-Hispanic immigrants who intermarried with Hispanics and integrated into the Californio culture during the Mexican era, and their descendants.

Calisphere and author Ferol Egan restrict the meaning of Californio to the Californian elite who acquired land during the Spanish and Mexican periods and their descendants.