This study investigated whether sleep problem severity in children with autism spectrum disorder was associated with maternal well-being. Mothers of 234 children reported on their mental health (Kessler Psychological Distress Scale), parenting stress (Parenting Stress Index-4-SF), health-related quality of life (HRQoL; Assessment of Quality of Life-4D) and their child’s sleep (Children’s Sleep Habits Questionnaire–ASD). Analyses revealed sleep initiation and duration problem severity scores were associated with increased mental health difficulties. Specific child sleep problems were not associated with parenting stress or HRQoL. This study revealed the importance of considering sleep and the family system when assessing maternal well-being. Future research considering parent, child and family factors will be important to informing a family focused approach to mental health.