Study Objectives: Up to 80% of children with autism spectrum disorder (ASD) experience sleep disturbance. Poor sleep impairs executive functioning (EF), a lifelong difficulty in ASD. Evidence suggests EF impairments in ASD is exacerbated by poor sleep. We examine whether early childhood sleep disturbances are associated with worsening EF trajectories in school-aged children with ASD. Methods: A subsample (n = 217) from the Pathways in ASD longitudinal study was analyzed. The Children’s Sleep Habits Questionnaire captured sleep duration, onset, and night awakenings before age 5 (Mean = 3.5 years). Metacognition (MI) and Behavioral Regulation (BRI) indices on the Teacher Behavior Rating Inventory of Executive Functioning measured EF difficulties at four time-points (7-11 years). We applied latent growth curve models to examine associations between sleep and EF, accounting for relevant covariates, including school-age sleep (Mean = 6.7 years). Results: Longer sleep onset at 3.5 years predicted a worsening BRI difficulties slope (b = 2.07, p < 0.04), but conversely predicted lower BRI difficulties at age 7.7 (b = -4.14, p = 0.04). A longer sleep onset at age 6.7 predicted higher BRI difficulties at age 7.7 (b = 7.78, p < 0.01). Longer sleep duration at age 6.7 predicted higher BRI difficulties at age 7.7 (b = 3.15, p = 0.01), but subscale analyses revealed shorter sleep duration at age 6.7 predicted a worsening inhibition slope (b = -0.597, p = 0.01). Conclusions: Different sleep phenotypes have different age-related impacts on selective behavioral regulation components, but not metacognition. Delayed sleep onset is a robust early predictor, whereas shorter sleep duration is a later predictor of worsening behavior regulation in school-aged children with ASD.