Physical activity (PA) benefits children with autism spectrum disorder (ASD). Evidence suggests that some barriers impede parents from providing PA support for their children with ASD. Parental perceived stigma is one of these barriers. However, few studies have explored how parental perceived stigma influences parental PA support. This study aimed to investigate the relationship between parental perceived stigma and parental PA support, the mediating role of parental self-efficacy, and the moderating effect of having other typically developing children or not. A total of 274 participants were recruited to participate in the study. The results showed that parental self-efficacy mediated the association between parental perceived stigma and parental PA support and the moderating effect of having other typically developing children or not.