Advanced Placement[R] (AP[R]) courses provide high school students an opportunity to be exposed to the rigors of college while they are still in high school. Since school policies play a role in the opportunities for students to pursue these courses, educational leaders must be aware of the ways in which their personal beliefs and school practices influence the course-taking patterns in their students. This study investigated the relationship between principals' personal beliefs and perceptions of school practices, and the opportunities for students to successfully complete rigorous Advanced Placement coursework. The study utilized a questionnaire distributed to 88 principals of schools belonging to the Chicago Area Directors of Curriculum and Assessment (CADCA). The questionnaire measured the personal beliefs of the principals and their perceptions of school practices surrounding six constructs: (1) Value of AP Coursework and Communicating That Value to Stakeholders, (2) General Course Offerings, (3) AP Placement Policies--Open vs. Limited Access, (4) Attracting More Students to AP Courses, (5) Teachers' Adaptability and Commitment to AP Expansion, (6) Expecting and Ensuring Success for Students in AP Courses. The data were analyzed using multiple regression analysis to determine the relationship between principals' responses and the school's AP Equity and Excellence Score, which measures the percentage of graduating seniors who had a successful AP experience. Research data indicated significant relationships between the AP Equity and Excellence Score and several research constructs. These findings can help school leaders formulate or re-examine policies that allow increasing numbers of students to successfully pursue academically-challenging coursework. By coming to a more complete understanding of the relationship between principals' personal beliefs and student success, this study contributes to the literature about the ways leaders provide opportunities for all students to learn to their full potential. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]