Although the majority of adolescents with autism spectrum disorder (ASD) rely on healthcare coverage through Medicaid during their transition into adulthood, little is known about their continuing eligibility. This study used Medicaid Analytic Extract (MAX) data to examine Medicaid coverage in a national sample using a cohort of adolescents with ASD ( n = 4,179) and a like-aged cohort with intellectual disability (ID, n = 21,844) over 5 years using survival analysis and Cox regression models. More than 1 in 4 adolescents with ASD lost coverage and fewer than half subsequently regained it. They were more likely to disenroll than adolescents with ID. Similarities in overall patterns among the 2 groups suggest that the experience of adolescents with ASD was characteristic of more general aspects of behavioral health coverage and indicate the need for programmatic reforms.