It is the position of the National Association of School Nurses (NASN) that immunizations are essential to primary prevention of disease from infancy through adulthood and that childhood vaccinations are an effective way of preventing serious childhood illnesses (U.S. Department of Health and Human Services [USDHHS], 2017). NASN supports elimination of all exemptions except those necessary for valid medical contraindications. School nurses are leaders who use evidence-based immunization strategies, such as School Located Vaccine (SLV) clinics, parent/guardian reminders about vaccine schedules, state immunization information systems (IIS), i.e., state registries, strong support of vaccination recommendations, and vaccine education for students, staff, and families. This document provides the background and rationale for NASN's position. [This position statement was initially adopted in June 1978 and was revised in June 1982, June 1996, November 2001, June 2006, September 2010, January 2015 (see ED558444), and January 2020.]