As rare diseases often have an onset of symptoms in childhood, the burden of the disease and associated challenges commonly fall to the individual’s family members. Managing this burden, and navigating these challenges, has been found to affect the health and lifestyle of family members and lead to them experiencing negative psychosocial impacts and lower quality of life. The aim of the current study was to consolidate and summarise the published quantitative evidence on the psychosocial impacts experienced by individuals who have a family member with a rare disease. We performed a systematic literature search including quantitative studies on psychosocial impacts experienced by family members of individuals with a rare disease across three databases (PubMed, PsychINFO, and CINAHL) from inception to November 2021. Of the 2024 titles identified, 30 studies met the inclusion criteria and were included in the review. A narrative analysis revealed that family members of individuals with rare disease experience a wide range of psychosocial impacts, some of which appear to be unique to, or amplified by, the rarity of the disease. Whilst there are occasional positive outcomes of having a family member with a rare disease, overall family members have been found to experience increased psychological distress, lower quality of life, higher caregiver burden and changes to their social support. Clinical and practical implications of these findings are discussed, as well as implications and directions for future research.