The authors evaluated the efficacy of RECAP, a psychosocial intervention developed to treat concurrent internalizing and externalizing problems in children. Participants included 93 4th-grade children assigned to the treatment group or a no-treatment control group. The school-based program, which lasts the 9-month academic year, provides individual, group, classroom, teacher, and parent training in the RECAP skills-development curriculum, which was derived from empirically supported treatment programs for nonconcurrent internalizing and externalizing problems. Outcome assessments included parent-, teacher-, self-, and peer reports. A mixed hierarchical linear models analysis indicated that, overall, treatment children's rate of improvement in both internalizing and externalizing problems was significantly greater than that for control participants.