 The relationship between Immanuel Kant (1724–1804) and David Hume (1711–1776) is a source of longstanding fascination. Kant credited Hume with waking him from his “dogmatic slumber”, and he describes the Critique of Pure Reason, arguably the most important work of modern philosophy, as the solution to the “Humean problem in its greatest possible amplification” (Prol 4:260–61). Much of the focus has been on their respective views in metaphysics and epistemology. Yet, as Thomas Nagel remarks, contemporary moral philosophy also “continues to be dominated by the disagreement between these two giants” (Nagel 2012). Comparing Hume and Kant therefore provides opportunity to clarify and assess two of the modern era’s most influential approaches to moral philosophy. Comparing their views also illuminates the landscape of eighteenth-century ethical thought. There are fundamental disagreements between them, but Kant and Hume share some central assumptions about morality, and Kant was directly influenced by the sentimentalist tradition to which Hume belongs (especially Francis Hutcheson’s version). The influence was most positive and pronounced early in Kant’s career, but it lingered long after he made a decisive break with this tradition.