The Roman Catholic Archdiocese of Tijuana () is a Metropolitan Archdiocese in Mexico. It is based in the city of Tijuana, Baja California, and the province has the suffragan dioceses of Ensenada, La Paz en la Baja California Sur, and Mexicali.
It was founded in 1855 as a vicariate for the Baja California's missions that were under the apostolic administration of the Archdiocese of Mexico City (until the 1848 Treaty of Guadalupe Hidalgo they were part of the Roman Catholic Diocese of California).
Pope Pius IX created the Apostolic Vicariate of Baja California in 1874. The see of the apostolic vicariate was in La Paz until 1939, later in Ensenada and, since 1944, in Tijuana.
In 1957 the southern part of Baja California became a separate apostolic prefecture (the current Diocese of La Paz en la Baja California Sur) and in 1963 the apostolic vicariate became the Diocese of Tijuana (Archdiocese since 2006).