Frailty is a common but complex phenomenon that is approached from theoretical and professional perspectives but rarely from the perspectives of older people and their essential stakeholders. Different or opposing perspectives on frailty at personal, organisational, and community levels can negatively affect care for frail older people. This systematic integrative review synthesises the perspectives on frailty of older people, health/social care professionals, informal caregivers, managers and policymakers, using thematic analysis. We use the Joanna Briggs Institute–Critical Appraisal Checklist to appraise the quality of 52 qualitative and mixed-method studies drawn from the PubMed/MEDLINE, CINAHL, PsycINFO, Embase, and Web of Science databases (inception–December 2023). Of these, 33 include the perspectives of older people, 27 of health/social care professionals, four of managers, and six of informal caregivers. Structuring the perspectives along six themes – ‘the multi-dimensional nature of frailty’, ‘the dynamics of frailty’, ‘the complexity of frailty’, ‘frailty in relation to age’, ‘frailty in relation to health’ and ‘frailty in relation to dependence’ – revealed substantive similarities in the conceptualisation of frailty between older people and professionals, e.g. regarding frailty’s dynamic and multi-dimensional nature. However, older people and professionals differ in their interpretations of frailty: older people take a personal view, while professionals take a more practical view. The identified discrepancies in perspectives may affect care relationships and care for frail older people. Therefore, we advocate a systems approach that incorporates multiple perspectives to form a comprehensive view of frailty and allows for a situation-specific shared understanding of frailty in older people.