Background: Social anxiety disorder (SAD) and depression are common among adolescents, frequently comorbid, and resistant to change. Prevention programs for adolescent SAD are scant, and depression prevention programs do not fully address peer-risk factors. One critical peer-risk factor for SAD and depression is peer victimization. We describe the development and initial evaluation of a transdiagnostic school-based preventive intervention for adolescents with elevated symptoms of social anxiety and/or depression and elevated peer victimization. We modified Interpersonal Psychotherapy-Adolescent Skills Training for depression, incorporating strategies for dealing with social anxiety and peer victimization. Objective: Our open trial assessed the feasibility, acceptability, and preliminary benefit of the modified program (called UTalk) for adolescents at risk for SAD or depression and who also reported peer victimization. Method: Adolescents (N = 14; 13-18 years; 79% girls; 86% Hispanic) were recruited and completed measures of peer victimization, social anxiety, and depression both pre- and post-intervention and provided ratings of treatment satisfaction. Independent evaluators (IEs) rated youths' clinical severity. The intervention (3 individual and 10 group sessions) was conducted weekly during school. Results: Regarding feasibility, 86% of the adolescents completed the intervention (M attendance = 11.58 sessions). Satisfaction ratings were uniformly positive. Intention-to-treat analyses revealed significant declines in adolescent- and IE-rated social anxiety and depression and in reports of peer victimization. Additional secondary benefits were observed. Conclusions: Although further evaluation is needed, the UTalk intervention appears feasible to administer in schools, with high satisfaction and preliminary benefit. Implications for research on the prevention of adolescent SAD and depression are discussed.