In 1999, the United States Department of Education began its Small Learning Community Program in an effort to support the breakup of large schools into smaller learning communities. In an effort to improve the academic success rate of students, President George W. Bush signed into law the "No Child Left Behind Act of 2001" (NCLB). NCLB had as its purpose, the closing of the gap in academic achievement between White students and the historically underserved student groups of African American, Hispanic/Latino(a), and low-income. Recently, there has been a lot of interest in how small learning environments effect the academic achievement of historically underserved students. In addition, several school districts, e.g. Chicago Public Schools, New York City, and Sacramento City Unified School District, have reformed their schools into comprehensive high schools with Small Learning Communities (SLCs) and small schools. Determining which of these two small learning environments is most effective in improving academic achievement can then be used to inform education policy regarding school design. This study used quantitative methods to determine if there is a difference in the academic achievement of African American high school students attending large urban high schools with small learning communities and those attending small urban high schools with student populations under 500. Independent samples "t"-tests were performed to determine if there was a statistically significant difference in the English Language Arts and Algebra 1 California Standards Test scores between African American high school students attending SLCs and African American high school students attending small schools. Additionally the research focused on the difference in the graduation and dropout rates between the two small learning environments. In none of the four measures of academic achievement studied did African American students in the large high schools with small learning communities outperform students in small schools. Based on the findings of this research--lower dropout rates, higher CST scores, and higher graduation rates in the small schools, school districts might consider creating small schools rather than breaking up large schools into SLCs. [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.]