Transition from pediatric to adult health care systems presents unique challenges for adolescents with autism spectrum disorder who often have complex medical and mental health needs. Without a coordinated transition plan, pediatric providers often continue to provide care to young adults with autism spectrum disorder beyond the scope of their medical training. Adult providers may be unwilling and untrained to accept care for young adults with autism spectrum disorder. This quality improvement study identified baseline transition-related practices within a pediatric medical home practice and developed a model to promote transition to adult heath care for patients with autism spectrum disorder. Participants were 251 patients with autism spectrum disorder aged 12-21 years. Baseline data revealed limited and inconsistent communication directed to patients and families regarding transition. An evidence-based and replicable transition checklist, templated documentation, and resources geared to patients aged 12-21 years were developed. While improvement was noted in number of visits addressing transition, medical providers skipped or deferred transition discussion in approximately half of well visits for targeted patients. Challenges in implementing the transition process included finding time to discuss transition-related issues with patients/families, preference of medical providers to defer to social work to address transition, and difficulty identifying adult providers with whom to collaborate regarding care needs.