Objectives: This study had two main objectives: first, to describe the social support and psychological maladjustment of children and adolescents with cerebral palsy (CP); and second, to test a mediation model where psychological maladjustment was hypothesized to mediate the link between social support and health-related quality of life (HRQL). In addition, the moderating role of gender and age was examined for this mediation model. Methods: Self- and proxy-report questionnaires on the aforementioned variables were administered to a sample of 96 children/adolescents with CP and 118 healthy controls, as well as one of their parents. Univariate and multivariate analyses of covariance were conducted to examine differences in social support and psychological maladjustment, respectively. PROCESS computational tool was used for path analysis-based mediation, moderation and moderated mediation analyses. Results: Children/adolescents with CP reported lower levels of social support than their healthy peers, but no significant differences emerged in terms of their psychological maladjustment. For children/adolescents with CP, internalizing and externalizing problems were found to mediate the link between social support and HRQL, and these indirect effects were not conditional upon age or gender. Discussion: Children and adolescents with CP are likely have more negative perceptions of social support, but not necessarily more psychological adjustment problems than their healthy, able-bodied peers. Results further suggest that interventions targeting social support perceptions may positively affect HRQL outcomes in children/adolescents with CP, through the improvement of internalizing and externalizing dimensions of their psychological adjustment. Implications for Rehabilitation Social support perceptions are important intervention targets in psychosocial rehabilitation with children and adolescents with CP. Children and adolescents with CP do not necessarily present increased psychological maladjustment. Interventions targeting these children and adolescents’ social support may promote their psychological adjustment and health-related quality of life. Developmental specificities, such as age and gender differences, should be considered when planning and implementing psychosocial interventions.