Bonhoeffer’s theological contributions may provide significant relevance and theoretical illumination on contemporary issues in ecclesiology. Not only did Bonhoeffer offer creative theological insights, but he also incorporated philosophy into his theological positions in a way that maintains the supremacy of theology. Specifically, Bonhoeffer develops an ecclesial theology, starting in Sanctorum Communio and extending throughout his writings, that relies on social theory and philosophy (especially Hegel) while simultaneously making theology the theoretical authority over these other disciplines. In his ecclesiology, Bonhoeffer argues for an ontological unity between the Church and Christ, which he calls the Christ-reality and Christ existing as Church-community. In his earliest work, Sanctorum Communio, Bonhoeffer develops his Christological ecclesiology that he later refines in his other writings. Within his theology of the Church, Bonhoeffer significantly uses liturgy in order to illuminate how Christ exists as the Church. This thesis will theologically and philosophically analyze Bonhoeffer’s theology of the Church’s ontological unity with Christ in order to explicate the theological realities involved with the Church acting as and being Christ’s body on earth.