Adherence to medication, especially insulin, is a key contributor to diabetes treatment outcomes. Lack of adherence is common among patients with type 1 diabetes mellitus (T1DM) ranging from 23% to 77%, with a higher frequency in developing countries. Poor adherence results in worse glycaemic control and increased mortality and morbidity due to diabetes complications. The objective of this study is to discuss insulin adherence among adolescents with T1DM. The review was conducted through search engines such as PubMed, Medline, Embase and Google Scholar. Search terms used were ‘type 1diabetes mellitus’, ‘insulin dependent diabetes mellitus’, ‘Juvenile diabetes mellitus’, ‘adherence’, ‘compliance’, ‘non adherence’, ‘barriers’, ‘omission’, ‘medical adherence’, ‘adolescents’, ‘teenagers’ and ‘insulin’. T1DM is challenging for adolescents due to its lifelong treatment regimens. Educational programmes and specific interventions which can improve affordability, accessibility and administration of insulin should be implemented to improve insulin adherence among adolescents.