There is an increasing prevalence of cancer in Africa with approximately 80% of cancers diagnosed at an advanced stage. High out-of-pocket healthcare costs and overstretched health systems lead to heavy reliance on informal carers for cancer care. This study aims to explore the roles and experiences of informal carers including the impact of cancer care on individuals and communities and support available for carers. We carried out a systematic review following PRISMA reporting guidelines and used critical interpretative synthesis to identify themes and develop an informal carers' experience framework. We searched nine databases and screened 8,123 articles from which 31 studies were included in the review. Most studies were from Sub-Saharan Africa (29/31, 94%), particularly Uganda (9, 29%). Carers were mostly women, aged 30-40 years, and siblings, spouses, or children. Caring roles included care coordination, fundraising, and emotional support. Caring was time-consuming with some carers reporting 121 hours/week of caring, associated with the inability to pursue paid work and depression. Four themes demonstrated carers' experiences: 1) intrapersonal factors: strong sense of familial obligation, and grappling with gender roles, 2) interpersonal factors: impact of a cancer diagnosis on households, changing social and sexual relationships, 3) community factors: navigating cultural norms on nature and location of care, and 4) health system influences: barriers to accessing healthcare services, and tensions between traditional and biomedical medicine. These themes aligned with Bronfenbrenner's social ecological model which aided our development of a framework for understanding informal carers' experiences'. Our review highlights multifaceted roles and experiences of informal carers in Africa, amidst cultural and community impacts. Carers experience a strong obligation and willingly undertake the role of carer, but at the expense of their social, economic, and psychological wellbeing. Support for carers, including flexible working hours/ carers' allowance, should be incorporated as part of universal health coverage.