The Cathedral of the Most Holy Savior and of Saints John the Baptist and John the Evangelist in the Lateran, also known as the Papal Archbasilica of Saint John [in] Lateran, Saint John Lateran, or the Lateran Basilica, is the cathedral church of the Diocese of Rome in the city of Rome, and serves as the seat of the bishop of Rome, the pope. The archbasilica lies outside of Vatican City proper, which is located approximately 4 kilometres (2.5 mi) to the northwest. Nevertheless, as properties of the Holy See, the archbasilica and its adjoining edifices enjoy an extraterritorial status from Italy, pursuant to the terms of the Lateran Treaty of 1929.

The church is the oldest and highest ranking of the four major papal basilicas as well as one of the Seven Pilgrim Churches of Rome, holding the unique title of "archbasilica". Originally founded in 324, it is the oldest public church in the city of Rome, and the oldest basilica of the Western world. It houses the cathedra of the Roman bishop, and has the title of ecumenical mother church of the Roman Catholic faithful. The building deteriorated during the Middle Ages and was badly damaged by two fires in the 14th century. It was rebuilt in the late 16th century during the reign of Pope Sixtus V. The new structure's interior was renovated in the late 17th century, and its façade was completed in 1735 under Pope Clement XII.