African American adolescent males rank at the top of every reported risk factor for poor achievement. In spite of gains made by the No Child Left Behind Act, the gap between African American adolescent males and every other ethnic and gender group has remained unchanged. The most recent long-term trend data released by the National Center for Education Statistics (2009) reveals a 53-point gap in reading proficiency between Black and White 17-year-olds. Research has begun in the last five years on the effects of single-sex classrooms for both genders as a result of flexible changes to Title IX legislation in 2004. An exhaustive search of the literature databases revealed no documented research completed to date to determine how single-sex education benefits African American adolescent males. The guiding research question in this study was: how do single-sex classes affect the self-efficacy of African American adolescent males in an urban middle school setting? Grounded theory design, from a constructivist approach, was the method chosen to explore the research question. Data collection included a survey questionnaire, a focus group discussion, and individual interviews conducted from a purposeful sampling of sixth-grade African American adolescent males in an urban middle school in southern Georgia. Data analysis concluded that single-sex classes do not affect, or change, the self-efficacy of African American adolescent males. The theory embedded in the data indicated that self-efficacy is impacted by smaller class sizes and the teacher-student relationship, but not as a result of single-sex instruction. More research is needed to determine how single-sex classrooms can best meet the academic needs of urban African American adolescent males.