The present study describes a comprehensive, day treatment program conducted in public school classrooms for children with serious emotional disorders (SED) and presents data evaluating program efficacy. Behavioral outcomes are presented for 142 children, ages 5 to 18 years, over the course of an academic year. Treatment efficacy was assessed using a behavioral outcome measure, the Youth Outcome Questionnaire. At initial evaluation, all children were exhibiting emotional symptoms beyond the scope of outpatient services, with 97% being classified as having a Severe Emotional Disorder. At the 9-month follow-up, 50.7% of the sample showed overall symptom reduction, and 27.5% scored below clinical cutoff levels, indicating remission of symptoms to within normal limits. Treatment response was equally likely among boys and girls, and across diagnostic categories. Elementary school-aged children and adolescents made equivalent gains in the program; however, mixed-model, repeated-measures ANOVA revealed a significant group × time interaction ( p < .05), indicating that these groups showed different patterns of improvement over time. © 2002 Wiley Periodicals, Inc. Psychol Schs 39: 661–675, 2002.