Parental involvement benefits children with autism spectrum disorder (ASD) in multiple developmental areas. We conducted the present study to examine the role of parenting stress and ASD symptom severity in the relationship between family socioeconomic status (SES) and parental involvement. A total of 165 Chinese parents of children with ASD participated in this study. Mediation analyses indicated that family SES was positively related to parental involvement; parenting stress partially mediated the relationship between family SES and parental involvement. The analyses also found that ASD symptom severity moderated the influence of parenting stress on parental involvement. Specifically, the decreased parenting stress improved parental involvement when ASD symptom severity was low. The findings enhanced our understanding of the mechanism underlying the relationship between family SES and parental involvement among parents facing considerable child-rearing challenges. Implications for devising evidenced-based interventions to promote parental involvement for low SES children with ASD are discussed.