This study assessed the effects of providing social participation rules on the performance and social behavior of a school-based sample of 10-14-year-old students at risk for attention deficit hyperactivity disorder (n = 34) who worked cooperatively in same-gender triads with typical peers (n = 92). The design was primarily a 2 (population group) x 2 (gender) × 2 (type of triads: with or without a group member at risk) x 2 (task condition: with or without the social rules of turn-taking, response-justification). The authors found that social interactive rules reduced negative verbal and off-task behavior, which was attributable to students at risk for attention deficit hyperactivity disorder and improved the percentage of problems solved for all children, which was attributable to boys and to middle school students. The intervention was discussed in terms of its practicality and educational importance. (Contains 2 notes, 5 tables, and 4 figures.)