The Diocese of Anagni-Alatri is a Latin Church ecclesiastical territory or diocese of the Catholic Church in Lazio, Italy. It has existed in its current form since 1986. In that year the Diocese of Alatri was united to the historical Diocese of Anagni. The diocese is immediately exempt to the Holy See.

Pope Stephen VI was the bishop of Rome and ruler of the Papal States from 22 May 896 to his death. He is best known for instigating the Cadaver Synod, which ultimately led to his downfall and death.