BACKGROUND: The global COVID-19 pandemic has left health and social care systems facing the challenge of supporting large numbers of bereaved people in difficult and unprecedented social conditions. Previous reviews have not comprehensively synthesised the evidence on the response of health and social care systems to mass bereavement events. AIM: To synthesise the evidence regarding system-level responses to mass bereavement events, including natural and human-made disasters as well as pandemics, to inform service provision and policy during the COVID-19 pandemic and beyond. DESIGN: A rapid systematic review was conducted, with narrative synthesis. The review protocol was registered prospectively (www.crd.york.ac.uk/prospero, CRD 42020180723). DATA SOURCES: MEDLINE, Global Health, PsycINFO and Scopus databases were searched for studies published between 2000 and 2020. Reference lists were screened for further relevant publications, and citation tracking was performed. RESULTS: Six studies were included reporting on system responses to mass bereavement following human-made and natural disasters, involving a range of individual and group-based support initiatives. Positive impacts were reported, but study quality was generally low and reliant on data from retrospective evaluation designs. Key features of service delivery were identified: a proactive outreach approach, centrally organised but locally delivered interventions, event-specific professional competencies and an emphasis on psycho-educational content. CONCLUSION: Despite the limitations in the quantity and quality of the evidence base, consistent messages are identified for bereavement support provision during the pandemic. High quality primary studies are needed to ensure service improvement in the current crisis and to guide future disaster response efforts.