Clavis Patrum Graecorum

The Clavis Patrum Graecorum ('Key (Glossary) of the Greek Fathers') is a series of volumes published by Brepols of Turnhout in Belgium. The series aims to contain a list of all the Fathers of the Church who wrote in Greek from the 1st to the 8th centuries. For each author it lists all their works, whether genuine or not, extant or not. Each work is assigned a number. The CPG number is widely used as a reference in scholarly literature. The text itself is written in Latin.

A corresponding Clavis Patrum Latinorum also exists for the Latin Fathers.

The two were created in order to facilitate publishing the Corpus Christianorum series of Latin and Greek texts.