Evidence-based clinical guidelines assist health care providers to ensure best practices. The National Association of School Nurses (NASN) has developed the organization's first evidence-based clinical guidelines to assist school nurses to practice at their highest level and in response to a direct request by members. This guideline focuses on asthma; more guidelines will follow. This article provides an overview identifying why clinical guidelines are important, how the guidelines were developed, and guidance to school nurses on how to interpret and use the guidelines.