This article calls for a sociological understanding of the importance of trust to aged care. It connects existing theories of trust to empirical evidence from gerontology and nursing research. Trust is defined as a response to and management of social vulnerability. It is argued this makes trust a fundamental concept for understanding human service and social care institutions, including aged care. In light of Australia's Royal Commission into Aged Care Quality and Safety, as well as generational shifts in consumer expectations and care ethics, the article highlights four distinct yet interrelated forms of trust: interpersonal, institutional, organisational and public trust. All of these forms are shown to be critical in conceptualising and evaluating the perceived trust deficit facing contemporary aged-care systems, and existing evidence shows how these forms of trust can reinforce, conflict and misalign with each other. Efforts to rebuild trust in aged care at an organisational and institutional level should ensure mechanisms facilitate rather than hinder the formation of interpersonal trust relations between individual service users, their families and aged care staff. Broader social policy reforms must also consider and address the way cultural understandings of ageing, and media representations of aged care, have diminished the public's trust in the sector, and how the cycle of scandals, reviews and piecemeal reforms contributes to this.