The word ‘ethics’ has two related meanings, both of which are important for this chapter. The fi rst is the familiar meaning of ethics as a set of substantive moral values, beliefs and practices. In this sense, ethics is about the distinctions we make, on an everyday basis, between right and wrong, asking ourselves questions such as: is it ethical to buy fruit originating from an oppressive regime? Or, is it ethical to have a gas-guzzling car in the context of global warming? The second meaning of ethics is more specialised, and refers to the philosophical study of the ways in which we justify our claims about right and wrong, asking questions such as: how do I know buying the fruit is or isn’t ethical? How do I know having the car is or isn’t ethical? The purpose of this chapter is to explore how substantive international ethical issues and questions about the basis of ethical claims in an international context are affected by bringing in a gender perspective to their consideration. We will begin by examining some of the dominant strands of international ethical theory and how they have been criticised by feminists. We will then move on to examine some examples of feminist international ethical theory. We will conclude by looking at how a gender perspective changes our perception of the moral stakes in relation to war, human rights and distributive justice.