This thesis aims to contribute to an answer to the question, “What would a philosophy, and more specifically, an ethics, based on Christ, look like?” My first contention is that we find, in the ethical thinking of Karl Barth and Dietrich Bonhoeffer, two particularly radical and complementary attempts to point toward Christ as the basis or foundation of any genuine ethics. What sets the views of Barth and Bonhoeffer apart from many of the other philosophical and theological approaches to ethics, is the extent to which they seek to take seriously the ethical implications of the gospel – the revelation of God's grace in the Word and work of Jesus Christ – for ethics. My second contention is that, even if we follow neither Barth nor Bonhoeffer in the detailed outworking of the character of a Christologically grounded ethics, we nevertheless cannot avoid facing the radical challenge each of these men poses, in their own related but distinct ways, that in thinking about ethics we must take Christ as our standard and foundation. In the first two chapters, on Barth and Bonhoeffer respectively, I identify the structure and content of their arguments and display their textual basis in the texts most relevant to the topic, namely Barth’s Church Dogmatics and Bonhoeffer’s Ethics. I also present an outline of the character of a Christologically-grounded ethics as each of these theologians derives it from its Christological basis. In the third chapter I examine the cogency of their arguments.