Background Families with a child diagnosed with autism spectrum disorder (ASD) often utilize a variety of professional services. The provision of these services has many potential benefits for families; however, these services also place demands on parents, particularly mothers, to access, navigate and participate. Little is known about how involvement with these services and service systems influences the psychological wellbeing of mothers of children diagnosed with ASD. We examined the relationship between professional services and psychological wellbeing for mothers of children diagnosed with ASD. Methods Mothers (n = 119) of children (mean child age 10.1 years; range 2–24 years) diagnosed with ASD anonymously completed a comprehensive survey. The survey included data related to maternal psychological wellbeing, professional services received and perceptions of these services, and child, mother and household characteristics. Results Regression analyses revealed that maternal psychological wellbeing was positively associated with the perceived continuity of services, and negatively associated with the number of professionals involved. Child and maternal age, and household income were also statistically significant predictors of maternal psychological wellbeing. Conclusions The study findings draw attention to the potentially negative impact of systems‐level challenges, especially fragmentation of services, on maternal psychological wellbeing, despite positive front‐line services. In particular, our data suggest that psychological wellbeing among mothers of children with ASD may vary more as a function of service system variables than practitioner‐level or child‐level variables.