The use of primary source materials is recognized as key to supporting inquiry-based history and social studies education. The extensive digitization of library, museum, and other cultural heritage collections represents an important resource for teachers as they strive to develop their students. critical thinking skills. Yet, searching and selecting digital primary sources appropriate for classroom use can be difficult and time-consuming. This study investigates the design requirements and the potential usefulness of a domain-specific ontology to facilitate access to, and use of, a collection of digital primary source materials developed by the University Library of the University of North Carolina at Chapel Hill (UNC-CH). During a three-phase study an ontology model was designed and evaluated with the involvement of social studies teachers identified as the primary community of end users. The findings revealed that the design of the ontology was appropriate to support the information needs of the teachers and was perceived as a potentially useful tool to enhance access and facilitate inquiry-based instruction. The primary contribution of this dissertation is the introduction of an approach to ontology development that is user-centered and designed to facilitate access to digital cultural heritage materials. This study also contributes to the growing body of literature on teachers. use of digital libraries and primary source materials, especially in the area of social studies education.