Alatri Cathedral, otherwise the Basilica of Saint Paul (Italian: Duomo di Alatri; Basilica concattedrale di San Paolo apostolo), is a Roman Catholic cathedral in Alatri, Lazio, Italy, dedicated to Saint Paul. It was formerly the cathedral of the Diocese of Alatri. Since 30 September 1986 it has been a co-cathedral of the Diocese of Anagni-Alatri. Pope Pius XII declared it a basilica minor on 10 September 1950.
The cathedral was built on what was once the centre of the acropolis of Alatri over the remains of an ancient shrine of the Hernici and of a temple dedicated to Saturn. References to a cathedral go back to the first half of the 11th century: a cathedral chapter is documented here in 930. Under Pope Innocent II (1130–1143), probably in 1132, the relics of the martyred saint Pope Sixtus I were translated here, and in honour of this the cathedral was refurbished: the main altar was completed in 1156. Further works took place through the 13th century, when in honour of the visit of Pope Honorius III the screen and the ambo, both by the Cosmati, were added, of which some traces still remain in the cathedral today.