Background: Individuals with diabetes and a learning disability have poorer health outcomes than those without a learning disability. In the UK, the health inequalities faced by people with learning disabilities are often the result of barriers they face in accessing timely, appropriate and effective health care. The aim of the study was to review relevant literature to identify the barriers and enablers to optimal diabetes care for adults with learning disabilities. Methods: Systematic review methodology was used to answer the research question: What barriers and enablers to optimal diabetes care exist for adults with learning disabilities? This review is reported according to PRISMA guidelines. Key databases were searched using relevant terms. Included studies were synthesised using thematic analysis and were quality appraised. Findings: This review identified 12 barriers to optimal diabetes care for adults with learning disabilities and 14 enablers to optimal care from 10 diverse publications. "Low level of diabetes knowledge and understanding" and "systems that do not allow reasonable adjustments" were the barriers considered to have the greatest reliability. The enabler identified to have the highest reliability was "person-centred planning and reasonable adjustments." Conclusion: This work highlights key actions that can be undertaken to address inequalities in diabetes care for people with learning disabilities. With additional research in this field, further progress can be made to improve the lives of those adults living with learning disabilities and diabetes.