Cross-sectional data from Fenning et al. (J Autism Dev Disord, 48:3858–3870, 2018) were used to examine age differences in processes related to the development of emotion regulation in children with autism spectrum disorder (ASD). Forty-six children with ASD between the ages of 4 and 11 years and their primary caregivers participated in structured laboratory tasks from which parental scaffolding and child dysregulation were coded. Moderation analyses suggested increased internalization of parental co-regulatory support with age, as evidenced by more coherence in dysregulation across dyadic and independent contexts and a stronger inverse relation between parental scaffolding and independent dysregulation. Children’s estimated mental age did not account for these effects. Implications for understanding and promoting the development of emotion regulation in children with ASD are discussed.