Background: Informal payments limit equitable access to healthcare. Despite being a common phenomenon, there is a need for an in-depth analysis of informal charging practices in the Sub-Saharan Africa (SSA) context. We conducted a systematic literature review to synthesize existing evidence on the prevalence, characteristics, associated factors, and impact of informal payments in SSA. Methods: We searched for literature on PubMed, African Index Medicus, Directory of Open Access Journals, and Google Scholar databases and relevant organizational websites. We included empirical studies on informal payments conducted in SSA regardless of the study design and year of publication and excluded reviews, editorials, and conference presentations. Framework analysis was conducted, and the review findings were synthesized. Results: A total of 1700 articles were retrieved, of which 23 were included in the review. Several studies ranging from large-scale nationally representative surveys to in-depth qualitative studies have shown that informal payments are prevalent in SSA regardless of the health service, facility level, and sector. Informal payments were initiated mostly by health workers compared to patients and they were largely made in cash rather than in kind. Patients made informal payments to access services, skip queues, receive higher quality of care, and express gratitude. The poor and people who were unaware of service charges, were more likely to pay informally. Supply-side factors associated with informal payments included low and irregular health worker salaries, weak accountability mechanisms, and perceptions of widespread corruption in the public sector. Informal payments limited access especially among the poor and the inability to pay was associated with delayed or forgone care and provision of lower-quality care. Conclusions: Addressing informal payments in SSA requires a multifaceted approach. Potential strategies include enhancing patient awareness of service fees, revisiting health worker incentives, strengthening accountability mechanisms, and increasing government spending on health.