Previous literature has demonstrated the separate contributions of parental attributions and adolescent attributions to psychosocial adjustment of adolescents with chronic illness. However, it is unknown whether parental attributions affect adolescents' mental health directly or indirectly by influencing the youths' attributional style. This study evaluated the direct and indirect (through adolescent attributions) effects of parental attributions on internalizing and externalizing problems of adolescents with chronic illness. Adolescents (N = 128; M = 14.7 years) diagnosed with cystic fibrosis or diabetes and their caregivers completed measures of attributional style and adolescent adjustment. Parents' optimistic attributions were associated with fewer adolescent internalizing and externalizing problems. These effects were partly mediated by adolescent attributions. These results suggest that targeting both adolescent and parent attributions may be important for improving adolescents' adjustment to a chronic illness. © Springer Science+Business Media, LLC 2012.