Does the fact that humans are vulnerable, needy and dependent beings play an important role in Kantian ethics? It is sometimes claimed that it cannot and does not. I argue that it can and does. I distinguish between broad (all persons are vulnerable) and narrow (only some persons are vulnerable) senses of vulnerability, and explain the role of vulnerability in both senses in Kantian ethics. The basis of this argument is to show that the core normative focus of Kantian ethics is on the dignity that human beings have in virtue of their capacity for rational agency. This implies that the empirical conditions under which human beings can acquire, sustain, exercise, and develop their rational capacities are of core moral importance in Kantian ethics. This explains why human vulnerabilities, including the vulnerability of human bodies, are important in Kantian ethics, since rational capacities in human agents (and the bodies those rational capacities depend upon) are highly vulnerable in all persons (vulnerability in the broad sense) and especially vulnerable in some sub-groups of persons (vulnerability in the narrow sense).