This article highlights the importance of System of Systems Engineering (SoSE) in achieving sustainability goals. System of Systems (SoS), as systems with significant and enduring environmental impact, play a critical role in overall sustainability efforts. The article first introduces the foundations of SoSE and Design for Sustainability. It then identifies eight essential capabilities for developing sustainable system of systems, emphasizing a holistic approach that considers processes, methods, technologies, people, and the environment. Finally, it outlines the challenges of such approach and indicates future work. Despite the difficulties associated with adopting this approach, the paper highlights the profound significance and implications that complex systems have on the environment in which they operate.