Background <p>Family caregivers play a central role in cancer and palliative care but often experience substantial emotional burden. Caregiver guilt has increasingly been recognised as clinically relevant; however, existing research has largely examined guilt as a secondary component of broader psychosocial outcomes. Evidence regarding how caregiver guilt is conceptualised, measured, and addressed across cultural contexts remains fragmented. This scoping review aimed to synthesise current evidence on caregiver guilt among family caregivers of patients with cancer and to examine its conceptualisation, measurement, and implications for palliative care.</p> Methods <p>A scoping review was conducted following the Arksey and O’Malley framework and reported in accordance with PRISMA-ScR guidelines. Thirteen English and Chinese databases were searched from database inception to 20 October 2025. Qualitative, quantitative, and mixed-methods studies examining guilt as a primary or secondary outcome among family caregivers of patients with cancer were included. Data were synthesised narratively to identify key themes across studies.</p> Results <p>Twenty-seven studies were included. The studies used qualitative, quantitative, and mixed-methods designs and were conducted across diverse cultural and care contexts. Caregiver guilt was reported in relation to perceived inadequacy in caregiving, difficult care-related decisions, self-care, family and relational responsibilities, emotional suppression, and uncertainty around prognosis or end-of-life care. Measurement approaches were heterogeneous, including standardised scales, brief guilt items, study-specific questionnaires, and qualitative methods. Six studies were conducted in direct palliative, hospice, end-of-life, or bereavement contexts, and five addressed advanced, incurable, prognosis-related, or otherwise palliative-relevant cancer caregiving. Limited intervention-related evidence was identified, including one feasibility study that included caregiver guilt as an outcome and one single-case intervention component reported in a master’s thesis.</p> Conclusions <p>Caregiver guilt is a recurring but inconsistently conceptualised experience in cancer caregiving. Based on the reported patterns across included studies, this review proposes an interpretive framework comprising two interrelated dimensions of caregiver guilt: action-oriented guilt and identity-oriented guilt. Future research should develop and test conceptually clear measures of caregiver guilt and evaluate interventions that address guilt-related distress across palliative and broader cancer caregiving contexts.</p>