Students must have a working understanding of the language of instruction to be successful in school. In the United States, English is the predominant language of instruction, and students who come from homes where a language other than English is spoken face the additional challenge of learning both subject matter content and the dominant language. Further, students who do not have the support and resources needed for successful language acquisition are more likely to fall behind academically and not graduate from high school. Similarly, for students to take advantage of advanced coursework, such as the International Baccalaureate (IB) program, they must be able to comprehend and excel at communicating using the English language. This non-experimental study analyzed the differences in IB English exam scores, rates of full IB program enrollment, and IB program completion, specifically among graduates from Lincoln College Preparatory Academy in the Kansas City Public School District. An ANOVA and Chi-square measurements found that these variables are not significantly related. While not explicitly part of this study, the performance of females on the IB English exam was analyzed for comparison between defined language groups. The statistically significant results of this ANOVA are included in the findings of this study. These results have implications for broader educational policy and practice to support all students' success in IB programs. [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.]