Background The COVID-19 pandemic impacted diabetes mellitus clinical outcomes and chronic care globally. However, little is known about its impact in low-resource settings such as sub-Saharan Africa. Hence, to address this, we systematically conducted a scoping review to explore the COVID-19 impact on diabetes outcomes and care in countries of sub-Saharan Africa. Methods We applied our search strategy to PubMed, Web of Science, CINAHL, African Index Medicus, Google Scholar, Cochrane Library, Scopus, Science Direct, ERIC and Embase to obtain relevant articles published from January 2020 to March 2023. Two independent reviewers were involved in the screening of retrieved articles. Data from eligible articles were extracted from quantitative, qualitative and mixed methods studies. Numerical data were summarised using descriptive statistics, while a thematic framework was used to categorise and identify themes for qualitative data. Results We found 42 of the retrieved 360 articles eligible, mainly from South Africa, Ethiopia and Ghana (73.4%). COVID-19 increased the risk of death (OR 1.30,9.0, 95% CI), hospitalisation (OR 3.30,3.73: 95% CI), and severity (OR: 1.30,4.05, 95% CI) in persons with diabetes mellitus. COVID-19 also increased the risk of developing diabetes mellitus in hospitalised cases. The pandemic, on the other hand, was associated with disruptions in patient self-management routine and diabetes mellitus care service delivery. Three major themes emerged, namely, (i) patient-related health management challenges, (ii) diabetes mellitus care service delivery challenges, and (iii) reorganisation of diabetes mellitus care delivery. Conclusion COVID-19 increased mortality and morbidity among people living with diabetes mellitus. In addition, the COVID-19 pandemic worsened diabetes mellitus care management. Sub-Saharan African countries should, therefore, institute appropriate policy considerations for persons with diabetes mellitus during widespread emergencies.