To address climate change, firms are increasingly forming sustainability alliances. Pursuing sustainability via such alliances is challenging as it means working with multifaceted and not necessarily compatible goals. Moreover, it often requires collaboration among heterogeneous partners outside traditional industrial contexts as well as dealing with wicked problems. This article presents a multiple-case study of eight sustainability alliances in Sweden, identifying managerial challenges and solutions over three phases where such alliances unfold. It offers a framework, tailored to each phase, to help companies fulfill their goals by proactively addressing the challenges posed by the pursuit of sustainability through alliances.