English form of Latin Gregorius, which was from the Late Greek name Γρηγοριος (Gregorios), derived from γρηγορος (gregoros) meaning "watchful, alert". This name was popular among early Christians, being borne by a number of important saints including Saint Gregory Thaumaturgus (3rd century), Saint Gregory the Illuminator (4th century), Saint Gregory of Nyssa (4th century), Saint Gregory of Nazianzus (4th century), and Saint Gregory of Tours (6th century). It was also borne by the 6th-century pope Saint Gregory I the Great, a reformer and Doctor of the Church, as well as 15 subsequent popes.
Due to the renown of the saints by this name, Gregory (in various spellings) has remained common in the Christian world through the Middle Ages and to the present day. It has been used in England since the 12th century. A famous bearer from the modern era was American actor Gregory Peck (1916-2003).