The purpose of this pilot study was to determine if participation in an aquatic exercise program improves sleep in children with Autism Spectrum Disorder (ASD). Participants included 8 children. An A-B-A withdrawal design was utilized. Each phase lasted for 4 weeks. The treatment included 60 min of aquatic exercise 2X/week. Phone calls to parents of the participants were made throughout the duration of the study. Parents were asked questions related to sleep latency, nighttime wakenings, and sleep duration. A one way repeated-measures analysis of variance (ANOVA) was utilized to determine if differences existed between phases. Statistically significant difference existed for sleep latency (p < 0.001) and sleep duration (p < 0.001). These results suggest that participation in aquatic exercise may improve the sleep habits of children with ASD.