Adolescents with ASD face numerous personal and contextual barriers that impede the development of social motivation and core competencies, warranting the need for targeted intervention. A randomized controlled trial was conducted with 40 adolescents to evaluate the merits of a multi-component socialization intervention that places emphasis on experiential learning. This investigation evaluated the impact of the 20-week START program on the social functioning of adolescents with ASD. Significant Group × Time differences between START and waitlist control groups were found across multiple measures. Secondary analyses of the entire program cohort also yielded significant improvement trends across all measures. These findings may be an important step in identifying optimal strategies to target the complex factors limiting optimal social development in ASD.