In the operations management literature, organizational learning has recently begun to emerge as an important missing link to successful lean transformations. As such, drawing on insights from two case companies in the engineer to order (ETO) industry, we frame the successful enhancement of supply chain capabilities through a lens we call “Lean and Learn”. Continuous improvement without learning is not lean thinking. Thus, lean thinking and practice is, in essence, a process of learning; where problems are identified and solutions are created, analysed, selected, and implemented; resulting not only in improved performance but also in improved capability. Since the ETO industry exhibits project-based production, there seems to be natural barriers and resistance to continuous improvement and learning. By building on the notion that an organization with an improved capability is an organization that has learned, this study examines the link between supply chain capabilities and organizational learning in an ETO context by combining analytical conceptual reasoning with meta-data collected from action research at two case companies. The study contributes to practice by pointing out how supply chain capabilities can be enhanced in an ETO context, and to academia by identifying and offering new knowledge to start filling the research gap between three specific research areas: ETO supply chains, organizational learning, and lean management.