The concept of moral responsibility has many applications. We speak, for example, of a person's responsibilities, and mean his professional or domestic commitments. In this sense a person can be said to have too many responsibilities, or none at all, and he can be said to be responsible to or for another person. Again, we can speak of the person himself as being responsible or irresponsible, and mean that he is conscientious and trustworthy in the performance of his duties or that he has a sense of responsibility. Finally, we can speak of a person as accepting responsibility for an action or another person. A thorough analysis of these complexities of usage would require the investigation of a number of background concepts, but in this paper I have the more limited object of classifying some of the usages. I propose to do this by constructing three analytical models based on the concept of a social role.