Autism spectrum disorder (ASD) is being more recognized and diagnosed in developing as well as developed countries. We aimed to investigate the frequency of anxiety, depression, and quality of life in mothers of children with ASD in Iranian families. We conducted a descriptive cross-sectional study on demographic data and mental health characteristics of 127 mothers of children with ASD. Mothers of children with ASD had high levels of anxiety (72.4%), depression (49.6%), and low scores of health-related quality of life (HRQOL). There was strong association between the child’s age and the severity of mother’s depression and QOL. Duration since diagnosis of ASD positively correlated with maternal depression. Anxiety, depression, and low HRQOL are more common in Iranian mothers with autistic children in our study. Our findings have implications for further investigation in mental health status of mothers of children with ASD, and providing educational support and interventional strategies may improve the mental health status of the entire family.