Diabetes mellitus (DM) is regarded as one of the most critical public health challenges of the 21st century. It has evolved into a burgeoning epidemic since the last century, and today ranks among the major causes of mortality worldwide. Diabetes specialist nurses (DSNs) are central to good patient care and outcomes including confident self-care management. Evidence shows that DSNs are cost-effective, improve clinical outcomes, and reduce length of stay in hospital. In this brief narrative review, we aim to describe the roles of DSNs and their contribution in the treatment and management of patients with DM. This narrative review describes the importance of DSNs in healthcare practice, in the inpatient and outpatient departments, in the pediatrics department, in managing diabetic foot ulcers, in the treatment and management of gestational diabetes, in prescribing medications for DM and in diabetes self-management education on glycosylated hemoglobin, and cardiovascular risk factors. To conclude, DSNs have a crucial role in the treatment and management of patients with DM and its complications. DSNs have a great impact on diabetes therapy, and hence implementation of DSNs and nurse-led diabetic clinics might be beneficial for the health care system. Finally, having DSNs might significantly contribute to good healthcare practice and support. Even though DSNs are not available in several regions around the globe, and even though this post is still new to several health care institutions, the presence of DSNs recognized and certified by the various healthcare systems would be very useful.