School nurses are answering a call to action to provide day-to-day care for an increasing number of students diagnosed with chronic illnesses. Diabetes mellitus is one of the most prevalent chronic health conditions identified among school-age children and presents a host of complex challenges for the school nurse, educators, and other support personnel to address in an effort to keep these children healthy and optimally prepared to learn. In working with this student population, it is critical that all educators possess an adequate working knowledge of type 1 and type 2 diabetes mellitus. This article provides a comprehensive overview of diabetes, including common measures and provisions necessary for managing students' daily needs, associated conditions that may compromise aspects of psychosocial and academic functioning, and commonly used medications and treatment plans for diabetes, with consideration for impact on students' daily school routines. Additionally, diabetes is reviewed within the context of multiple disabling conditions, with an emphasis on the psychological and behavioral features. Guidance and recommendations are offered to adequately prepare and position school nurses and other school-based personnel to fully support the student with diabetes in the school setting.