["Business Strategy and the Environment, EarlyView. ", "\nABSTRACT\nDrawing on multilevel and complexity theories, this research identifies new and reframed core principles of circular business ecosystems (CBEs), thereby clarifying what makes a business ecosystem circular. Although CBEs are increasingly recognised as adaptive systems shaped by interdependencies and non‐linear interactions, how circularity operates across ecosystem levels remains underexplained. Multilevel and complexity theories provide the analytical basis for distinguishing and connecting the CBEs' dimensions and dynamics through which circularity emerges. A systematic literature review was conducted using Coleman's boat model to explore how circular economy principles are integrated into ecosystem configurations. It examines (i) specific dimensions of CBEs related to ecosystem actors (including orchestrators, participants and complementors) and the relational dynamics among them; (ii) the value creation processes and the impacts generated by CBEs; and (iii) contextual factors influencing these systems. Overall, this work advances CBE research by explaining how circularity emerges from the interaction between macro‐ and micro‐level elements, showing how macro‐level association, situational, relational and transformational mechanisms shape these ecosystems.\n"]