Purpose: The purpose of this study was to analyze ethnic and gender differences in Advanced Placement (AP) exam performance of U.S. high school students. Specifically, the extent to which differences exist in overall AP exam performance scores within and between four ethnic groups (i.e., Asian, Black, Hispanic, and White) was investigated. Within each ethnic group, the extent to which gender differences exist was determined. Finally, an analysis of these differences over a 16-year time period was conducted to determine the extent to which national trends was present in overall AP exam performance. Methodology: To ascertain the ethnic and gender differences in overall AP exam performance by U.S. high school students, a nonexperimental, causal-comparative "ex post facto" research design was utilized. After 16 years of archival data from the College Board for the 1997 through the 2012 school years were downloaded, Pearson chi-square tests were conducted to determine whether statistically significant ethnic and gender differences in AP performance were present for Asian, Black, Hispanic, and White students. For statistically significant results, effect sizes were calculated to determine the level of practical significance. Findings: For the 16 years of data, Asian students had higher overall AP performance scores than did White, Black, and Hispanic students. All statistical analyses yielded statistically significant results, revealing either trivial or small effect sizes. Within each ethnic group, the overall AP performance of males exceeded the performance of females. Comparing ethnicity and gender differences revealed a consistent stair-step achievement gap wherein. Asian and White males outperformed Asian and White females; Hispanic males outperformed Hispanic females who outperformed Black males who outperformed Black females. Although Hispanic and Black students exponentially increased their participation in AP exams, their passing AP exam scores declined. Moreover, Black males and Black females underperformed all other groups. Due to the large numbers of failing exam scores, a negative trend in the cost effectiveness ratio for Black and Hispanic students represented the potential for millions of dollars wasted on AP expansion policies by public funding. Thus, the AP program needs to undergo a critical evaluation of its methods to provide college readiness for disadvantaged 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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]