The controversial reformer Martin Luther was no paragon of virtue. He was a polarizing figure and a bundle of seeming contradictions. Nevertheless, he offered important insights for ethical deliberation. He understood the flaws of human nature and the need for ethical realism. He promoted the idea of freedom of conscience. He helped encourage moral literacy and service to neighbours. He understood the paradoxical nature of ethical choices and the important role of public opinion. This lecture will examine Luther’s 16th-century contributions to public ethics and how they can inform a 21st-century view of the world and our place in it.