The use of intention in ethics has been the subject of intense debate for many years, but no consensus has emerged over whether intention is morally relevant, or even how it should be understood. In this paper I wish to make a thorough, though by no means exhaustive, examination of the concept and the concepts around it, some to be seen as near-synonyms, and some as contrasting ideas. My interest is in the ethical use of the concept, though my own (...) analysis of it will be indebted to discussions in the philosophy of action. The most famous ethical use, which will not, however, be my direct focus here, is the ‘principle of double effect,’ which states that an agent may cause or allow something bad as long as, first, no evil is intended as an end or a means; and, second, that the foreseen bad is not out of proportion with the anticipated good. It is important to note the principle’s testimony to the plausibility of prohibitions expressed in terms of intentions, and, alongside these, a general prohibition on doing inordinate harms even without intention. (shrink)