The education of students with disabilities has been subject to consistent growth and reform within the United States. Federal acts and initiatives continue to pave the way towards increasingly inclusive educational programs. Mainstreaming, the process of providing students in special education access to the same resources as their similar-grade peers, is a widely adopted methodology in the education of exceptional students. This study addresses the practice of co-teaching, the utilization of trained pairs of teachers representing both general education and special education to provide for a respectively diversified classroom population. Co-teaching is broadly praised as an effective tool for meeting aspirational initiatives in the education of students in special education. However, there exists little quantitative research examining the relationship between classroom structure and successful academic outcomes. The purpose of this quantitative study was to examine the academic growth of a group of students in special education from a partnered school district. Data was examined for a group of 13 students who participated in a traditional, separated special classroom structure for a full school year, followed by a year of sole participation in an integrated, co-taught, setting. This study utilized the MAPs Growth Assessment, a national assessment tool that the students participated in quarterly as part of their curriculum. The researcher examined the relative academic growth for the students in special education between each classroom setting. This study accounted for student growth in both mathematics and English-Language Arts (ELA). This study also intended to examine quantitative data on teaching practices between general education and special education teachers from the partnering district. However, the sample size for this data was too small to be analyzed. Results for the special education students did not indicate significant differences in academic growth for ELA or mathematics between the two classroom structures. These results were limited by small sample size and significant variance in individual student performance. Although no significant trends were observed, the results underscore the importance of individual student factors, as well as the further quantification of educational studies. Suggestions to account for these limitations in future academic studies are provided. [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.]