The present study compared the course of parent-report and actigraphy-derived sleep profiles over a 1-year period, in school-age children with autism spectrum disorder and typically developing children. The Children’s Sleep Habits Questionnaire and 14 nights of actigraphy were used to assess sleep profiles. Parents also completed the Spence Children’s Anxiety Scale, the Social Worries Questionnaire and the Bedtime Routines Questionnaire. Between-group differences in parent-reported sleep problems were less pronounced at follow-up compared to baseline. The course of objective sleep was comparable between groups, with a significant reduction in sleep duration over time in both groups. Children with autism spectrum disorder were further characterised by significantly more night-to-night variability in sleep quality, across both time points. Reductions over time in parent-reported sleep problems were significantly associated with reduced anxiety. Reductions in actigraphy-derived sleep efficiency were associated with an increased frequency of maladaptive activities in the hour before bedtime, in both children with and without autism spectrum disorder.