The FRIENDS for Life program is a cognitive-behavioral group program that targets anxiety in children. The main purpose of this study was to analyze the effectiveness of the Portuguese version of the FRIENDS for Life Program, which was implemented in schools to reduce anxiety problems in a group of highly anxious children. The study used a quasi-experimental research design with two groups of children, an intervention (n = 17) and a wait-list control group (n = 21), aged 8 to 12 years old. The impact of the program in reducing anxiety symptoms as assessed by children and mothers was analyzed through the Screen for Child Anxiety Related Emotional Disorders-Revised (SCARED-R). The results show a statistically significant post intervention effect on anxiety symptoms evaluated by the child, but not by the mother. The implications of these results for the prevention of anxiety disorders in Portuguese schools are discussed.