According to the National Association of Single-Sex Public Education (NASSPE, 2010), an increase of 540 public schools offering single-sex classrooms in the United States has occurred since 2001. Educators who understand the gender differences between boys and girls can inspire students to learn to the best of their ability; however, the problem with this increase is that the educators and school officials generally begin these single-sex classrooms/schools without enough education or training in gender differences and how boys and girls learn differently. The purpose of this study was to ask teachers who taught in single-sex classrooms to provide data for future professional development workshops/seminars that address the complexities of gender differences in their classroom environments. Thirty-one educators from a mid-size suburban Colorado community single-sex classroom charter middle school were invited to participate in the study. Volunteer participants were asked to join a focus group, complete a survey, and participate in interviews. The focus group participants piloted the survey and suggested changes, which led to further refinement of the survey questions and topics. The participants who filled out the survey answered questions about their need for information about gender differences, human development, psychological development and issues, curricula and teaching materials, lesson planning, and classroom management. The data collected from the surveys were shared in one-on-one interviews, which allowed for further discussion of the results and gave participants the opportunity to discuss any areas of concern. Finally, the results from all three sources of data were organized and shared with the school administration, board, and faculty. The results from the survey indicated that teachers in the study wanted more information and training on the gender differences in the brain and cognitive development, classroom management techniques, motivational techniques, and strategies for dealing with behavioral issues. These results support what the NASSPE (2010) reported is needed to provide the optimal opportunities for student success. The data provided by the participants can be used for customizing possible future professional development opportunities, for them and possibly for other single-sex and co-educational teachers. [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.]