Business ethics is usually taught either from a philosophical perspective that derives guiding normative principles from abstract theories of philosophical ethics or from an atheoretical perspective that has students analyze cases that present difficult ethical issues and propose solutions on a casuistic basis. This article proposes a third approach—the Principles Approach—that derives guiding normative principles teleologically from the nature of market activity itself. The article demonstrates how the Principles Approach can meet the four main challenges facing those who teach ethics in business schools—the challenges of definition, abstract, cultural relativism, and integration.