An effort was made to assess the relative effectiveness of different reinforcement systems versus traditional teaching with maladjusted boys. The subjects were 60 boys in grades 6 and 7 who participated during language arts classes, but total data were gathered on 26 boys. The boys had histories of aggressive behavior and language problems. Treatment consisted of the systematic application of reinforcement principles, including the use of peer-group reinforcement. The subjects were observed for 10 seconds at the first minute of every 5 minutes using a behavior problem checklist designed for the study. Their reactions to group and individual reinforcements were noted and compared to reading achievement. Among the findings were that subjects improved consistently in appropriate social behavior and in most cases group reinforcement proved superior to individually distributed reinforcers. Significant correlations were obtained between characteristics measured by the checklist, academic gains, and social behavior. Tables and a bibliography are included. (MS)