This paper analyses the question whether, and if so, under what conditions, a supply chain law could have a positive impact on the existing social and ecological conditions. Since supply chains represent one of the most important levers for business to create positive impact in the world, a supply chain law generally has great potential to make a positive contribution. Compared to voluntary commitments it can be assumed that a law would increase the willingness of companies to implement sustainable supply chain measures. Furthermore, it can be assumed that a regulation or at least a directive at the EU level would mitigate the risk of a competitive disadvantage of companies that are investing in sustainable supply chain measures compared to those companies that are not taking comparable steps. The real potential of a supply chain law, however, depends on the specific regulation, influenced essentially by the concrete provisions, the responsibility scope, the implementation flexibility and the penalty mechanisms.