This chapter examines how we should think about ethics, starting with three framing questions: Do states and their citizens have significant moral duties to the members of other countries? Should states and their militaries be morally constrained in the conduct of war? Who is morally responsible for the alleviation of global poverty? The chapter proceeds by defining ethics and considering three significant and difficult ethical issues entailed by globalization: cosmopolitanism, statism, and realist ethics. It concludes by examining the ethical dimensions of global poverty and just war. Two case studies are presented, one dealing with the ethics of migration and the other with the ethics of just war. There is also an Opposing Opinions box that debates who bears most responsibility for addressing global warming.