We evaluate people and groups as responsible or not, depending on how seriously they take their responsibilities. Often we do this informally, via moral judgment. Sometimes we do this formally, for instance in legal judgment. This article considers mainly moral responsibility, and focuses largely upon individuals. Later sections also comment on the relation between legal and moral responsibility, and on the responsibility of collectives. The article discusses four different areas of individual moral responsibility: (1) Responsible agency, whereby a person is regarded as a normal moral agent; (2) Retrospective responsibility, when a person is judged for her actions, for instance, in being blamed or punished; (3) Prospective responsibility, for instance, the responsibilities attaching to a particular role; and (4) Responsibility as a virtue, when we praise a person as being responsible. Philosophical discussion of responsibility has focused largely on (1) and (2). The article points out that a wider view of responsibility helps explore some connections between moral and legal responsibility, and between individual and collective responsibility. It also enables us to relate responsibility to its original philosophical use, which was in political thought.