The purpose of this study was to understand professional development for paraprofessionals supporting students with ASD in Virginia. This understanding was reached through explanatory, sequential mixed methods design. Surveys and interviews provided insight into training practices, training needs, and training barriers. An interpretation of their professional development was developed through considering the perceptions of paraprofessionals supporting students with ASD, teachers of students with ASD, and directors of special education. Findings revealed a lack of supervision, training, and skills. The lack of training and supervision resulted in paraprofessionals learning through trial and error. Paraprofessionals supporting students with ASD felt qualified to complete their duties as a result of personal disposition and effective supervision. Paraprofessionals supporting students with ASD desired individualized training concerning behavior management. The results of this study provide several recommendations for training content and delivery format. It also provided a theoretical framework for explaining how paraprofessionals supporting students with ASD experience training. [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.]