For most firms, the development of sustainable supply chain practices remains challenging. Using a theory-building approach, we develop a theory of socio-ecological intergradation to provide managers with guidance in mimicking natural ecosystems to develop more local and thus sustainable supply chains. Socio-ecological intergradation refers to the gradual merging of social (organizational) and ecological (environmental) systems to shift a firm's focus from global supply chain optimization to building more regionally bound, socio-ecologically connected operations. Drawing on the natural and industrial ecology literature, the paper identifies five principles that mimic natural ecosystems and increase the environmental sustainability of supply chains, including the ecological systems they ultimately depend on. The paper further illustrates what these principles mean in both an environmental and a supply chain context and how, in concert, they can lead toward more sustainably designed and managed supply chains. In building a theory of socio-ecological intergradation, this research is one of the first attempts to apply ecological principles to supply chains, creating synergy and dialogue between the sustainable supply chain management, business ethics, and industrial ecology disciplines.