 There is a strong research imperative to investigate effective treatment options for adolescents and adults with autism spectrum disorder (ASD). Elevated social anxiety, difficulties with social functioning and poor mental health have all been identified as core treatment targets for this group. While theoretical models posit a strong bidirectionality between social anxiety and ASD social functioning deficits, few interventions have targeted both domains concurrently. Of the two group interventions previously conducted with adolescents and adults with ASD, significant results have only been observed in either social anxiety or social functioning, and have not generalised to changes in overall mood. The aim of this study was to evaluate the potential benefit, tolerability and acceptability  of a group cognitive-behaviour therapy (CBT) intervention in young adults with ASD. Primary treatment outcomes were social anxiety symptoms and social functioning difficulties; secondary outcomes were self-reported mood and overall distress.