ABSTRACT:Although the literature on multi-stakeholder initiatives for sustainability has grown in recent years, it is scattered across several academic fields, making it hard to ascertain how individual disciplines, such as business ethics, can further contribute to the debate. Based on an extensive review of the literature on certification and principle-based MSIs for sustainability, we show that the scholarly debate rests on three broad themes : theinputinto creating and governing MSIs; theinstitutionalizationof MSIs; and theimpactthat relevant initiatives create. While our discussion reveals the theoretical underpinnings of the 3Is, it also shows that a number of research challenges related to business ethics remain unaddressed. We unpack these challenges and suggest how scholars can utilize theoretical insights in business ethics to push the boundaries of the field. Finally, we also discuss what business ethics research can gain from theory development in the MSI field.