In the pursuit of continuous improvement in education and closing the achievement gap, educators are experimenting with different environments that will assist students in increasing academic achievement. The media bombards Americans with news about the failing educational system that is being outperformed by counterparts around the world. In this study, the researcher presents evidence on whether assignment to a single-sex math class influences student achievement, teacher and administrator perceptions of student performance, and student engagement. Using a phenomenological approach, the researcher collected qualitative data by interviewing 10 teachers and two school leaders currently working in sex-specific public middle and high school leadership academies in a metropolitan area in Texas. Audio files were transcribed into text files and hand-coding was used to identify themes in the data. The study results contribute to the body of knowledge surrounding the perceptions of teachers and administrators on the effectiveness of single-sex math classes. [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.]