Principals in K-12 education face increasingly complex responsibilities and must maximize student learning within the boundaries of available funding and staffing. Effective library programs have been correlated to higher test scores and can be a resource for principals to meet improvement goals. The purpose of this Delphi study was to describe the knowledge, skills, and dispositions needed by K-12 administrators to direct effective school library programs. Across three expert profile groups, 23 panelists participated in three rounds of the Delphi process. A high level of consensus led to 44 statements of application for aspiring and practicing administrators. The four highest ranked items were statements of dispositions about the library program. Implications for administrators in preparation and practice are noted.