Purpose: The purpose of this study was to examine advanced coursework completion rates, Advanced Placement (AP)/International Baccalaureate (IB) testing rates, AP/IB exam passage rates, and the percentage of AP/IB exam scores at or above the criterion that may exist among Texas public high school students from 2001 to 2012 to ascertain (a) the extent to which differences exist by demographic variables (i.e., ethnicity) and (b) the extent to which these differences have changed from 2001 to 2012. Methodology: To ascertain the extent to which ethnic differences were present in advanced course participation and performance by Texas students, a nonexperimental, causal-comparative research design was utilized. After downloading 11 years of archival data from the Texas Education Agency for the 2001 to 2012 school years, inferential statistical procedures were conducted to determine whether statistically significant differences in advanced course access, exam completion, and examination performance were present for Asian, Black, Hispanic, and White students. Furthermore, analyses were conducted to determine the extent to which differences in Advanced Placement/International Baccalaureate access and performance were evident across ethnic groups. Findings: Statistically significant differences were present for all variables analyzed, with moderate to large effect sizes. In all of the statistical analyses, Asian students had the highest percentage of advanced course access and performance followed by White students, Hispanic students, and Black students. These stair-step gaps in achievement remained or worsened over the past 11 years. Despite educational reforms and aggressive enrollment of Black and Hispanic students into advanced courses, results from this study demonstrated little progress for these students on the AP/IB examinations. Furthermore, exam performance for all Texas students in the study either stagnated or declined over the past decade. Results from this study concurred with recent state and national research on the continued ethnic disparities on AP access and performance. Policymakers are urged to scrutinize the continued funding for subsidizing exams fees. Further research on the effectiveness of other rigorous curriculum options was recommended. Continued inequalities in academic achievement favoring Asian and White students over their Black and Hispanic peers will have long-term impacts on the state's future economy. [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.]