In recent years, St. Cyril of Alexandria has received growing scholarly attention. Never losing cite of his exceptional contribution to the articulation of the seminal aspects of Christian doctrine, Cyrillian scholarship moved to explore related aspects of his teaching on the Trinity, the Eucharist, the Church, the Spirit, and Scripture. Many areas of his teaching still remain virtually unexplored — one of which is the notion of the priesthood of Christ, a crucial point of contention during the Nestorian Controversy. This dissertation examines three aspects of Cyril's priestly Christology: his understanding of Christ as teacher, sacrifice and sanctifier. The notion of Christ's priesthood is doctrinally integral to the whole of Cyril's thought, including his reflections on the Eucharist, the Trinity, the Church, sanctification, divine filiation, anthropology, grace and pastoral ministry. This dissertation argues that tracing the development of Cyril's theology of Christ's priesthood throughout his oeuvre imparts indispensable insight into the overall development of his theological doctrine. It also provides a schema that aids in determining the dates of composition for many of his works, as well as his unique synthesis of eastern and western authors.