This chapter introduces the range of ethical concepts and approaches to ethical analysis required in global health work, and outlines the frameworks of principles that have been applied within clinical medicine, public health and global health. In the most general terms, ethics seeks to provide an account of how humans, as agents, assign and evaluate the worth of persons, organizations, their actions and their consequences. Ethics is distinct from the law in that it addresses issues related to interpersonal duties and obligations that are not regulated or compelled by external authority. Ethical theories aspire to provide a comprehensive, consistent and defensible normative account of moral activity. Descriptive ethics relates to accounts of how humans actually behave in the world. In religious ethics, fidelity to the dictates of faith, as indicated by the sacred texts, is of critical importance. Ethical theories and ethical frameworks will direct practitioners to the substantive issues informing an analysis of an ethical dilemma.