Over the past half century, a discourse emphasizing environmental constraints and limits has both informed and provided many valuable ways of responding to complex environmental problems and has strongly shaped green building practices and associated environmental assessment methods. This paper delineates the concept of 'regenerative sustainability' - a net-positive approach to sustainability that is rooted in the notion of 'procedural sustainability' and a particular stream of constructivist social theory. The paper contrasts this to the concept of 'regenerative development and design' which, although having many commonalities, is based on different philosophical underpinnings. Since the origins of regenerative sustainability and regenerative design lie primarily in the social and ecological domains respectively, understanding their relationship is of importance in formulating approaches for the successful co-evolution of human and natural systems. The paper describes this relationship between regenerative sustainability and regenerative design, including a discussion of some of the key points of convergence and divergence between them, and concludes with an exploration of the practical implications of the regenerative sustainability concept.