Objective: Describe and synthesise existing published research on the experiences and support needs of informal caregivers of people with multimorbidity. Design: Scoping literature review. Primary database and secondary searches for qualitative and/or quantitative English-language research with an explicit focus on informal carers of people with multimorbidity (no date restrictions). Quality appraisal of included papers. Thematic analysis to identify key themes in the findings of included papers. Results: Thirty-four papers (reporting on 27 studies) were eligible for inclusion, the majority of which were rated good quality, and almost half of which were published from 2015 onwards. The review highlights common difficulties for informal carers of people with multiple chronic illnesses, including practical challenges related to managing multiple health care teams, appointments, medications and side effects, and psychosocial challenges including high levels of psychological symptomatology and reduced social connectedness. Current gaps in the literature include very few studies of interventions which may help support this caregiver group. Conclusion: Interest in this research area is burgeoning. Future work might fruitfully examine the potential benefits of audio-recorded health care consultations, and digitally delivered psychosocial interventions such as online peer support forums, for supporting and enhancing the caring activities and wellbeing of this caregiver group.