Many young adults with autism spectrum disorder experience poor transition outcomes in key areas, including postsecondary employment, higher education, health care, social connectedness, and independent living, yet we lack a clear understanding of the specific factors that impact these outcomes. We reviewed qualitative research in which the perspectives of youth and young adults with autism spectrum disorder, parents, services providers, and other stakeholders were gathered to identify barriers and facilitators to optimal outcomes. Findings revealed that poor transition outcomes are influenced by several factors, including poor person-environment fit, uncertainty about the roles of parents, and the lack of comprehensive or integrated services. These findings also revealed the aspects of familial, organizational, and policy contexts that may be targeted for interventions. Finally, stakeholders emphasized that supports should be individualized and focused on the changing aspects of the young adult's social and physical environment rather than behavior change. We discuss implications for policy and practice and provide recommendations for further research.