This chapter introduces a model for school libraries in Scotland, based on best practices as identified in the literature, and on five case studies undertaken in schools, two in the United States and three in Scotland. The research design was qualitative, and used grounded theory and multiple case study methods. The model represents an ideal set of circumstances for school libraries in Scotland, highlighting the interconnected web of influences that affect the success of a school library in meeting professional standards. These influences primarily fall in three areas: the school librarian, the school environment, and the professional support available to the librarian. The school librarian is the primary leader of the school library program, but factors in these other two areas can provide opportunities and barriers that can help or hinder the success of the library service. For instance, the findings suggest that school-based factors such as curriculum, scheduling, technology facilities, and staffing can have significant influence over the access the librarian has to teachers and students. Our model includes all three areas in describing a set of circumstances that would allow a school library program to thrive and meet the highest professional standards.