This study was conducted to explore the perceptions of gifted students and their teachers on the relationship between the implementation of a differentiated curriculum designed to meet the needs of gifted students and the development of intellectualism. In this mixed methods study data was gathered using an online teacher survey, teacher interviews, student focus groups, and a document analysis of the descriptions of five widely implemented programmatic and curricular models. The results indicated that both gifted students and their teachers perceive the development of intellectualism to be congruent with the purposes and outcomes of a differentiated curriculum as defined by the GATE Standards, California Department of Education (2005). Impediments to the development of intellectualism identified by the students and teachers included a prescribed curriculum, the structure of the school day, excessive testing, untrained principals, and student goal orientation. The analysis of the programmatic and curricular models indicated that the structure of each model was congruent with the development of intellectualism. However, an analysis of the descriptions of a differentiated curriculum and the mission statements of schools and districts currently implementing each model indicated inconsistencies between the immediate and long-term goals of the schools and districts as they related to the development of intellectualism. The results of this study implied that professional development opportunities for teachers and principals need to include intellectual challenge and that efforts need to be made to develop a mastery goal orientation for gifted students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]