The current study examined the moderating role of friendship quality on the relation between maternal anxiety and internalizing symptoms in a 3-year prospective study of adolescent development. Participants included 177 adolescents (Mage = 16.05, SDage = 0.91) and their mothers. Mothers reported their own levels of anxiety; youth completed self-reports of internalizing symptoms and friendship quality. Positive friendship quality moderated the relation between maternal anxiety and initial levels of internalizing symptoms. Maternal anxiety was associated with steeper increases in internalizing symptoms over time, but only for those with greater negative peer interactions. Findings underscore the important role of both parental and peer relationships in the development of internalizing symptoms and highlight specific avenues for clinical interventions.