Philosophers usually discuss responsibility in terms of responsibility for past actions or as a question about the nature of moral agency. Yet the word responsibility is fairly modern, whereas these topics arguably represent timeless concerns about human agency. This paper investigates another use of responsibility, that is particularly important to modern liberal societies: responsibility as a virtue that can be demonstrated by individuals and organisations. The paper notes its initial importance in political contexts, and seeks to explain why we now demand responsibility in all spheres of life. In reply, I highlight the distinctively institutional character of modern liberal societies: institutions specify many of the particular responsibilities each of us must fulfil, but also require responsibility to sustain them and address their failings. My overall argument is that the virtue of responsibility occupies a distinctive place in the moral needs, and moral achievements, of liberal societies; and this, in turn, explains why it now occupies such a prominent place in our moral discourse.