This article explores the relation between ownership and sustainability on a conceptual level. It specifically examines different imaginaries of sustainable property by asking how private property rights and their restrictions are conceptualized as instruments for sustainability. To do so, conflicting notions of property that underlie Western jurisprudence and political theory are contrasted. This brings us to the identification of two major traditions in property thought that build on atomist or relational conceptions of society and property, respectively. Property might be conceived as an owner’s exclusive control over an object, or as a ‘bundle of rights’ that comprises entitlements, restrictions, and obligations to various actors. Largely within the paradigm of modernization as a trajectory of sustainability, these two fundamental traditions in property theory relate to different approaches to encode sustainability into property law: i) propertization, i.e. the extension of private property forms, as in the case of carbon emissions trading schemes; ii) the acknowledgment of social and environmental obligations inherent to property, illustrated by the social obligation norm in German law.