Backgrounds: Schools struggle to support health needs of students with diabetes due to limited funding/resources. A competency framework can help individual schools clarify the knowledge and skills required for school-based diabetes care within their unique context, and inform the development of standardized diabetes education for health staff. Methods: A consensus-building technique, known as the Delphi method, was used to create a competency framework for diabetes care at school with a panel of 37 stakeholders. A continuing education program based on the resultant framework was developed and pilot-tested with school nurses. Pretest and post-test scores on knowledge, perceived competence, and self-efficacy were compared to evaluate the effectiveness of the program. Results: Consensus was obtained for a total of 70 competencies: 22 competencies for health aids, 36 additional competencies for school nurses, and 12 additional competencies for diabetes resource nurses. Thirty school nurses completed the continuing education program and demonstrated significant improvement in diabetes knowledge, self-efficacy, and competence in pathophysiology and diabetes care tasks (p < 0.01 for all). Conclusions: Developing a consensus framework is an excellent starting place for stakeholders to identify the skills and knowledge required for various school personnel and to ensure that all school health staff members receive adequate diabetes education.