Previous studies suggest that children with Autism Spectrum Disorder (ASD) are more prone to develop sleep problems and sensory reactivity, and these symptoms have an impact on parental mood. The current study examined the sleep problems and atypical sensory behaviour of 48 first-time diagnosed ASD children and the anxiety/depression levels of their mothers. We also investigated factors associated with maternal depressive symptoms. We found that sleep problems, atypical sensory reactivity, and mothers' depression levels were higher in ASD children. Sleep problems and sensory reactivity were also significantly associated with mothers' depression and autism severity. In regression analyses, parasomnia and sensory reactivity were significant predictors of mothers' depression. Our results indicate that sleep-related symptoms and atypical sensory reactivity should be considered in all children diagnosed with ASD. In addition, our findings emphasize the importance of paying attention to caregiver distress and depression during the process of autism detection and intervention.