Background Oesophageal cancer surgery is extensive with high risk of long-term health-related quality of life (HRQL) reductions. After hospital discharge, the family members often carry great responsibility for the rehabilitation of the patient, which may negatively influence their wellbeing. The purpose was to clarify whether a higher caregiver burden was associated with psychological problems and reduced HRQL for family caregivers of oesophageal cancer survivors. Material and methods This was a nationwide prospective cohort study enrolling family members of all patients who underwent surgical resection for oesophageal cancer in Sweden between 2013 and 2020. The family caregivers reported caregiver burden, symptoms of anxiety, depression, post-traumatic stress, and HRQL 1 year after the patient’s surgery. Associations were analysed with multivariable logistic regression and presented as odds ratios (OR) with 95% confidence intervals (CI). Differences between groups were presented as mean score differences (MSD). Results Among 319 family caregivers, 101 (32%) reported a high to moderate caregiver burden. Younger family caregivers were more likely to experience a higher caregiver burden. High-moderate caregiver burden was associated with an increased risk of symptoms of anxiety (OR 5.53, 95%CI: 3.18–9.62), depression (OR 8.56, 95%CI: 3.80–19.29), and/or posttraumatic stress (OR 5.39, 95%CI: 3.17–9.17). A high-moderate caregiver burden was also associated with reduced HRQL, especially for social function (MSD 23.0, 95% CI: 18.5 to 27.6) and role emotional (MSD 27.8, 95%CI: 19.9 to 35.7). Conclusions The study indicates that a high caregiver burden is associated with worse health effects for the family caregiver of oesophageal cancer survivors.