There was a need for an increased and equal partnership between school professionals and parents. Collaboration will help parents and school professionals to understand one another. Natural environment teaching and routine should be incorporated into the intervention strategies that address the needs of the children diagnosed with autism. When parents and school professionals are trained with the proper skills to address their children's needs, children diagnosed with autism will be able to generalize learned skills to different settings such as playground, at home, and at school. The participants in the study were special education teachers, school psychologists, and parents who have children with autism and worked with students with autism. The participants are from New York state public suburban school district that served pre K. to 8th grade levels. One high-need school and one low-need school was selected. The purpose of the study was to investigate how applied behavioral-analysis usage by parents, teachers, and psychologists, parenting education in applied-behavioral analysis provided by schools, and collaboration among parents, teachers, and psychologists influence the behavioral, academic, social, self-help, and communicative performance of the children diagnosed with autism spectrum disorder. Furthermore, this study examined how teachers, parents, and psychologists compare in their description of applied-behavioral analysis usage, parenting education in applied behavior analysis provided by schools, and collaboration efforts about applied behavior analysis among parents, teachers, and psychologists and their impact in the lives of children diagnosed with autism spectrum disorder. The result demonstrates that applied behavioral-analysis usage by parents, teachers, and psychologists, parenting education in applied-behavioral analysis provided by schools, and collaboration among parents, teachers, and psychologists was highly effective in enhancing the behavioral., academic, social., self-help, and communicative performance of the children diagnosed with autism spectrum disorder. There were no differences in the description of applied-behavioral analysis usage, parenting education in applied behavior analysis provided by schools, and collaboration efforts about applied. behavior analysis among parents, teachers, and psychologists between the high. and the low-need school districts. [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.]