Behavioral sleep education has shown promise in young children with autism spectrum disorder (ASD), but has received much less study in adolescents with ASD. A pilot study of a brief sleep intervention was delivered to 18 adolescents, ages 11–18 years, and their parents. This sleep education, delivered in a two-session format, was associated with improved sleep onset delay, sleep efficiency, and other sleep parameters and sleep hygiene in adolescents with ASD during that time period. In this manuscript, the focus is on the impact this intervention and the sleep outcomes, presented in another manuscript, had on daytime behaviors. Significant improvements were seen following treatment in a direct objective measure of impulsivity and attention. A broadband parent report measure of behavior indicated significant improvements in anxiety, depression, somatization, atypical behaviors, and activities of daily living. A more focused parent report measure also indicated improvements in hyperactivity/noncompliance and lethargy. This brief behavioral sleep education program shows promising results in not only improving sleep hygiene and sleep onset latency for adolescents with ASD, but also having an impact on daytime behaviors.