This study examined whether self-stigma content and process would prospectively influence parental warmth and hostility through increasing parenting stress among parents of children with autism spectrum disorder (ASD). On three occasions across two years, 441 Hong Kong parents of children with ASD provided questionnaire data. Path analyses showed that self-stigma content and process were associated with greater parenting stress, which was, in turn, associated with reduced parental warmth and increased parental hostility. Our findings reveal the longitudinal influences of self-stigma on parenting practices and demonstrate how these influences can be explained by parenting stress. Our findings also suggest the importance of supporting parents of children with ASD to mitigate self-stigma and associated parenting stress in improving their parenting practices.