In this paper I attempt to explore the significance of the terms ‘accident’ and ‘chance’ when they are used in connection with events that are sometimes said to happen ‘by accident’ and sometimes ‘by chance’. The significance of these terms is not always made clear in everyday conversation, and here I shall try to discuss the distinction between them and the sorts of situation therefore to which they properly apply. Perhaps an example will show that these expressions are different. Thus ‘I met Smith in the library by chance’ is different from ‘I met Smith in the library by accident’, different because these statements reflect different interpretations of the events referred to. We see accidental and chance events in a different light. And this is the point; ‘accident’ and ‘chance’ are terms of interpretation, not of description. And I hope to show that the expression ‘by chance’ is appropriate in contexts which develop as a result of human decisions and intentions in a way in which the expression ‘by accident’ is not appropriate.