San Juan Bautista is a city in San Benito County, in the U.S. state of California. The population was 2,089 as of the 2020 census. San Juan Bautista was founded in 1797 by the Spanish under Fermín de Lasuén, with the establishment of Mission San Juan Bautista. Following the Mexican secularization of 1833, the town was briefly known as San Juan de Castro and eventually incorporated in 1896. Today, San Juan is a popular tourist destination, as the home of the San Juan Bautista State Historic Park and other important historic sites, as well as cultural institutions like El Teatro Campesino.

The Mexican Secularization Act of 1833, officially called the Decree for the Secularization of the Missions of California, was an act passed by the Congress of the Union of the First Mexican Republic which secularized the Californian missions. The act nationalized the missions, transferring their ownership from the Franciscan Order of the Catholic Church to the Mexican authorities.