Children with Asperger's Syndrome (AS) are failing academically, despite the availability of educational, financial, and medical resources for them. This could be explained by the reliance of educational processes on traditional direct instruction that leads to poor academic performance of students with AS. Classroom format and environment are said to affect student performance, particularly students with autism spectrum disorders. The current study was designed to look at whether students with AS achieve better in (a) mainstreamed, (b) inclusive, or (c) self-contained classes using the self-efficacy and optimal stimulus theories as frameworks. A quantitative method was the main research approach to answer these questions. Survey research data was collected to (a) identify which classroom format produces the highest academic achievement for students with AS, and (b) identify specific factors, such as classroom size and time of day, that support academic achievement in mainstreaming, inclusive, and self-contained formats. Classroom teachers who were directly responsible for teaching students with AS were asked to participate in answering the surveys. Administrators with oversight responsibility were also asked to participate in the survey questions. The study was significant, because the findings may help in improving the educational outcomes of students with AS. The results of the data analysis showed that there was a statistically significant difference in test scores based on the type of classroom in which the students received instruction. In addition, students who received instruction in mainstream classroom had significantly higher test scores than the students who received instruction in the inclusive and self-contained classrooms. Furthermore, students who received instruction in the mainstream classrooms did not have mean test scores that were iii significantly different from the standard score. In contrast, the students who received instruction in the inclusive classrooms and the self-contained classrooms had mean test scores that were significantly lower than the standard score for the test. The important implication of those results is the traditional view that inclusive classrooms are better than other classroom formats for students with Asperger's syndrome is not correct. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]