Purpose Fear of cancer recurrence (FCR) may be equally prevalent, persistent and burdensome in cancer caregivers as in survivors. This systematic review evaluated FCR prevalence, severity, correlates, course, impact and interventions in cancer caregivers. Methods Electronic databases were searched from 1997 to May 2021. Two reviewers identified eligible peer-reviewed qualitative or quantitative studies on FCR in adult caregivers or family members of adult cancer survivors. The risk of bias was assessed using the Cochrane Risk of Bias tools for randomised and non-randomised studies and the Mixed-Methods Appraisal Tool. A narrative synthesis and thematic synthesis occurred on quantitative and qualitative studies, respectively. Results Of 2418 papers identified, 70 reports (59 peer-reviewed articles, 11 postgraduate theses) from 63 studies were included. Approximately 50% of caregivers experienced FCR. Younger caregivers and those caring for survivors with worse FCR or overall health reported higher FCR. Most studies found caregivers' FCR levels were equal to or greater than survivors'. Caregivers' FCR was persistently elevated but peaked approaching survivor follow-up appointments. Caregivers' FCR was associated with poorer quality of life in caregivers and survivors. Three studies found couple-based FCR interventions were acceptable, but had limited efficacy. Conclusions FCR in caregivers is prevalent, persistent and burdensome. Younger caregivers of survivors with worse overall health or FCR are at the greatest risk. Further research on identifying and treating caregivers' FCR is required. Implications for Cancer Survivors Caregiver and survivor FCR are similarly impactful and appear interrelated. Addressing FCR may improve outcomes for both cancer caregivers and survivors.