Many studies have documented adaptive behavior deficits in individuals with autism spectrum disorder (ASD). A considerable body of work has also catalogued challenges in adult outcome attainment amongst autistic individuals; notably, relatively strong adaptive function is associated with a higher likelihood of attaining some adult outcomes in this population. To date, little work has examined whether competency in specific adaptive behaviors increases the likelihood of attaining adult outcomes. This study sought to address this gap via item set and item-level analyses of scores from a common adaptive behavior measure, the Vineland Adaptative Behavior Scales, from ages 5, 9, 14, and 18 in a well-characterized longitudinal cohort. Item sets related to cooking and personal hygiene predicted adult employment and subjective well-being at multiple ages. Individual items related to community skills (i.e., money management, rules, rights, and safety, restaurant skills, etc.) emerged as significant predictors of adult employment, social relationships, living status, and subjective well-being. Implications for adaptive behavior interventions are discussed.