The study topic was general education teacher perceived self-efficacy regarding their ability to develop and deliver lessons and implement classroom and instructional strategies for engaging students with autism spectrum disorder (ASD) in the general education classroom. The research problem was that teachers face changes in their roles and additional responsibilities, as children with ASD are increasingly educated within the general education classroom. A qualitative, collective case study was used to gather information from 12 certified general education teachers from Cyprus, who worked in an inclusive classroom with students diagnosed with ASD. Three domains of teacher self-efficacy, student engagement, classroom management, and instructional strategies served as the theoretical framework for the study. Data collection instruments included semistructured interviews, the Teacher Self-Efficacy Scale, and a modified version of the Autism Attitude Scale for Teachers-Revised. The data from the surveys were collected and organized; frequency, and mean values were reported on all items. Participant interviews were transcribed verbatim, and then coded according to theme. A constant comparison method of coding was used, prominent codes were defined, and then 10 common themes were determined: (1) teacher comfort when teaching students with autism spectrum disorder; (2) level of comfort when managing the classroom; (3) specific interventions and teaching methods; (4) strategies used when developing lesson plans; (5) perceived importance of effective classroom management; (6) perceptions of managing the classroom; (7) specific classroom management techniques; (8) proposed changes about educational services; (9) learning and training methods; and (10) learning interests. Teachers scored low in the two questionnaires which measured their perceived self-efficacy. They felt they could engage students with ASD in the classroom, assist families in helping their children do well in school, but they felt they could not do much to get to the most difficult students, or to improve the understanding of a student who is failing. The findings from the AAST survey showed that teachers hold somewhat favorable perceptions of educating students with ASD in an inclusive classroom. However, the results from the interviews also indicated that teachers did not have a high sense of self-efficacy, and did not feel very comfortable due to minimal training and limited knowledge in working with students with ASD. More studies could examine methods of professional collaboration and the performance of students with ASD through case studies in correlational research. [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.]