Concerns about the unsustainability of the conventional food system have brought attention to so called alternative food networks, which are widely thought to be more sustainable. However, claims made about AFNs’ sustainability have been subject to a range of criticisms. Some of them present counterevidence, while others have pointed to problematic underlying features in the academic literature and popular discourse that may hamper our understanding of AFNs’ sustainability. Considering these criticisms, together with the fact that the literature often addresses a (...) specific type of AFN or a specific sustainability-related issue, it is hard to form a clear overall picture of the sustainability promise of AFNs. In this article, we seek to contribute to a clearer understanding of this promise through a structured review, focusing on links between AFN characteristics and sustainability. Through an analysis of AFN conceptualizations reflected in the literature, we identify and consolidate their key characteristics. We then synthesize claims of how these characteristics may translate into sustainability, finding a wide range of potential direct and indirect impacts. Examining these from different angles, we find that the sustainability promise of AFNs found in these claims is qualified by the presence of potentially unaddressed issues, by criticisms regarding for example the evidence base of the assumed impacts and their power in addressing sustainability, and by considerations of how these impacts might play out in actual, real-life food networks. Indirect impacts of learning and participation may be highly significant for sustainability. We conclude with recommendations for research and practice. (shrink)