Despite the strong linkage between sustainable development and investment, older international investment agreements (IIAs) have been criticized as threatening the sustainable development of the host State. In recent IIAs, a slight shift towards taking the principle into account can be observed. However, the adoption of a sustainable‐development‐oriented approach in investment law depends largely on the tribunals that are tasked with the interpretation of IIAs. This article examines the role of arbitrators in promoting sustainable development. Despite their current reluctance to engage in a sustainable development discussion, the situation may alter with the conclusion of so‐called new generation free trade agreements. These agreements make more references to the principle and place at the arbitrators’ disposal interpretative tools for the integration of sustainable development into their argumentation. Finally, the article reflects on changes that would render the investment regime more compatible with sustainable development.