This study utilized a qualitative case study interview methodology to explore the transition to postsecondary education and first-year postsecondary educational experiences of four students with Autism Spectrum Disorders (ASD). This research provided a comprehensive understanding of the first-year postsecondary educational experience of the students who were enrolled in a private, selective four-year postsecondary educational institution. It explored the ecological factors that impacted the students' first-year postsecondary experiences through analyzing the perspective of the students, the students' parents, and the students' disability resource and service (D/RS) provider. It also investigated how students' prior experience and perception of ASD influenced their first-year postsecondary experience. Reviewed literature found that research focusing on postsecondary educational experiences was scarce and mainly consisted of anecdotal accounts of students with ASD and limited research on the experiences of students with ASD after their first year. There was no prior research focusing on the first-year postsecondary experiences of students with ASD. The study's findings provide an analysis of each student's prior experience and first-year postsecondary educational experience and then present a cross-case analysis. The study revealed that the students' academic and transition services in high school and parental support were the most notable prior experiences that influenced the students' transition to postsecondary education. It also found that the students experienced academic and social successes and challenges. Internal attributes, including students' persistence and stress impacted their experience. Parental support and D/RS support were perceived to have positively impacted the students' experience. The study also found that the students perceived their diagnosis of ASD as both a positive asset and a hindrance to their experience. The discussion provides an analysis of the factors within the postsecondary environment and from the students' prior experience that impacted their first-year and how these four students' experiences related to the previous literature. It also discusses the importance of implementing effective support services. Recommendations for policy, practice, and further research are also 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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]