The pursuit of economic opportunity has frequently put transnational manufacturing enterprises in the spotlight, accused of contributing to, if not causing, economic hardship, social deprivation, unsustainable growth, labour exploitation, resource plundering and ecological degradation in home and host countries. A substantial part of international trade now consists of intra-firm sales, or commercial transactions between units of the same business corporation, within or beyond the national borders of the parent company. Known as transfer pricing and viewed as a legitimate business opportunity by transnational corporations, it is often used to misrepresent financial success and evade taxation. This has recently instigated many fiscal agencies and governments to take more draconian measures than ever before to protect national financial interests. However, while the fiscal legality of transfer pricing practices is now carefully scrutinized, the heightened interest in its tax aspects has neglected the considerable ethical issues it entails. Unethical transfer pricing behaviour consumes scarce resources, causes costs but does not create value. This paper identifies and discusses some of these ethical issues and assesses their implications for the internalisation of trade, the design of transfer pricing systems, and international tax rules. Opportunities for future research are also outlined.