This article reports findings of a second randomized controlled trial of an early education classroom mental health intervention, Sunshine Circles. Sunshine Circles is an attachment-based play group intervention designed to assist children in feeling safe at school, develop social competencies, and improve emotional regulation skills. A previous study of the intervention found medium to large effect sizes across several measures of behavior and academics. The current trial enrolled 189 racially diverse preschool students in the United States, many of whom are refugees from high conflict regions. Sunshine Circles, which is led by specially trained teachers in their own classrooms, showed greater improvement across several bands of behavior and academic measures than did control classrooms. A description of the intervention is included. Implications for using this intervention with traumatized and chronically stressed young children are discussed. (author abstract)