This chapter examines the subject of humanity as created in the image and likeness of God, a central theme in the Christian mystical tradition. Indeed, the imago Dei forms the foundation of much if not all Christian theological anthropology, and questions of the ‘nature’ and ‘structure’ of the human person are evidently central to questions of the mystical encounter between human persons and God. This chapter first surveys the scriptural background of the imago Dei in both Genesis and the New Testament and then provides a brief survey of current systematic-theological and historical-theological approaches. After providing some background to patristic imago Dei theologies in both the East and West, the chapter focuses in-depth on three lesser-known medieval authors: John of Fécamp, William of St Thierry, and John of Ruusbroec, in an attempt to highlight the rich variation and theological sophistication of their mystical anthropologies.