In couples parenting children with Autism Spectrum Disorder (ASD), the partner becomes a primary source of support for addressing the additional parenting demands. The purpose of this study was to examine the associations between supportive dyadic coping and parental adaptation, and to assess the mediating role of relationship satisfaction between them. Seventy-six couples parenting children with ASD participated. Data were gathered through self-report questionnaires and an Actor-Partner Interdependence Mediation Model was used. Mothers' and fathers' supportive dyadic coping was related to both their own and partner's relationship satisfaction and parental adaptation. Findings also revealed the mediation role of relationship satisfaction, in the association between supportive dyadic coping and parental adaptation. The implications for research and clinical practice are discussed.