The present study evaluated the effectiveness of a universal school-based cognitive behavior prevention program (the FRIENDS program) for childhood anxiety. Participants were 638 children, ages 9 to 12 years, from 14 schools in North Rhine-Westphalia, Germany. All the children completed standardized measures of anxiety and depression, social and adaptive functioning, coping strategies, social skills, and perfectionism before and after the 10-week FRIENDS program and at two follow-up assessments (6 and 12 months) or wait period. Children who participated in the FRIENDS program exhibited significantly fewer anxiety and depressive symptoms, and lower perfectionism scores than children in the control group at 12-month follow-up. Younger children (9-10-year-olds) displayed treatment gains immediately after the intervention, whereas older children (11-12-year-olds) showed anxiety reduction only at 6- and 12-month follow-up. Perfectionism and avoidant coping acted as mediators of pre- to postintervention changes in anxiety scores. This study provides empirical evidence for the utility of the FRIENDS program in reducing anxiety and depressive symptoms among German children. (Contains 2 tables and 1 figure.)