The purpose of this study was to investigate the differences of Measures of Academic Progress (MAP) scores between fourth-grade African American male students who were enrolled in single-sex classrooms and their counterparts who were enrolled in coeducational classrooms. The research provided descriptive data concerning one Title I school in rural South Carolina that offered the single-sex option for students in first through fourth grade. The conceptual framework for this study is based on the work of Stanberry (2011), who asserts that single-sex classroom instruction is tailored to meet differing needs of differing sexes. Younger and Warrington (2002) also reported that parents and students found many advantages to the single-sex classroom format, including fewer distractions, increased confidence levels, and greater student involvement. The participants of this study were fourth-grade African American male students enrolled in single-sex and coeducational classrooms within the same rural elementary school in South Carolina. The researcher utilized quantitative methodology and non parametric statistics to compare the Measures of Academic Progress (MAP) mathematics and reading scores between the participants in single-sex and coeducational classrooms over a two-year period. Two-tailed t tests of independent means were used to analyze the data. The findings of this study provided mixed results. However, an increase in mathematics and reading scores between the two groups was evidenced in the 2010-2011 academic school year. During the first year of the study, participants in single-sex classrooms scored significantly higher in mathematics and reading than participants in coeducational classrooms. During the second year of the study, there was no significant difference between the single-sex and coeducational classrooms. Results from this study demonstrated that there may be value in the single-sex education option for students; and that further support of the option could be a factor in academic achievement at the participating school. Further studies on the subject of single-sex education are recommended for practitioners and researchers alike. A longitudinal study of academic achievement among students in single-sex classrooms in South Carolina, including students who are enrolled in single-sex classrooms for consecutive years, may be of great merit. A study of the academic achievement of African American male students who are instructed by African American male teachers would provide valuable information concerning the impact of role models on academic success. Finally, this researcher recommends that studies which disaggregate data by race, ethnicity, and gender could add to the current body of research on the single-sex instructional paradigm. [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.]