The growth of global value chains (GVCs) and the emergence of novel forms of value chain governance pose two questions for normative business ethics. First, how should we conceptualize the relationships between members of a GVC? Second, what ethical implications follow from these relationships, both with respect to interactions between GVC members and with respect to achieving broader transnational governance goals? We address these questions by examining the emergence of transnational eco-labeling as an increasingly prominent form of GVC governance that (...) is redefining the relationship between nominally independent firms. On the first question, we argue that GVCs occupy a middle ground between intrafirm and interfirm transactions, thereby posing a challenge to theoretical frameworks that attempt to apply ethical standards based on transaction types. On the second question, we argue that this unique institutional status leads to a range of novel ethical considerations and dilemmas for GVC members. Lead firms, their suppliers, and third-party standard-setters all confront new ethical quandaries when third-party eco-labeling is introduced to a GVC. The nature of these quandaries means that, while GVCs may be well-positioned to serve as instruments of transnational governance, they are frequently not well-oriented to do so. Our analysis marks an initial attempt to map the ethical considerations that apply to members of a GVC, and in doing so, places the literature on normative business ethics and transnational governance in a closer conversation. (shrink)