In this paper we introduce the concept of ‘(in)significance’ as a way to think about values in heritage, and in the attribution, recording, description, assessment and categorisation practices that characterise heritage processes. Our aim is to throw light on how this concept shapes, and is shaped by, contemporary heritage practices and outcomes. We consider the history of the idea of significance, particularly as it is defined in the Burra Charter, and trace its inheritance lines in settler nation states and capitalist economic structures, and highlight its retention of concepts of heritage value as both intrinsic and culturally attributed. Using international, mainly Anglophone examples, we review a range of case studies and examples of significance and insignificance, of significance assessment in practice, and the tensions between expert, institutional or ‘official’ values and broader concepts of heritage and attachment. We suggest that the dual or layered concept of ‘(in)significance’ might allow for heritage practices that interact with emotions, memory, place and things in ways that are often not possible in the context of official heritage regimes because of rigid aesthetic and conservation paradigms, as well as identity and ownership claims and deeply invested national narratives.