The ritualistic elements central to Greek tragedy are found in Peter Shaffer’s theatre, where the playwright has successfully revived Classical theatre on the modern stage. This thesis looks at three ritualistic plays in which the playwright makes use of masks, chorus, ideas of revenge and justice as well as myth on the modern stage. Considering The Gift of the Gorgon (1993) as Shaffer’s ultimate success in the revival of a ritualistic theatre, this thesis examines the evolution of this idea from The Royal Hunt of the Sun (1964), where masks and primitive rituals are placed on stage, to Equus (1973), where chorus and a Greek stage setting are added, and finally to The Gift of the Gorgon which can be considered Shaffer’s ultimate “Greek play”. In The Gift of the Gorgon. Shaffer uses not only elements from Classical theatre, but the play itself explores ancient Greek ideas of revenge and justice, which are central to Greek tragedy. Moreover, Shaffer’s plays are also self-reflexive, they are plays about drama. In Equus, the symbolism of modern theatre (bourgeois plays about everyday life and the struggle of normal people) and the sacredness in ritualistic theatre are discussed and contrasted. Furthermore, through the ideas of worship and existentialism, Peter Shaffer expresses his opinion on the meaninglessness of ritual in modern organised religion. He further attempts to show how theatre, which has its origins in religion, can still bring about catharsis and healing which modern organised religion has largely eliminated.