Anti-social behavior is reported to be a growing problem in school systems of different countries. A comparison was made about anti-social adolescent behaviors between students who attend single-sex schools and coeducational schools in Jamaica. Students (N=112) were interviewed to determine the most prevalent school discipline problems. A sample of 1,193 adolescents from 16 schools was then surveyed to determine the prevalence of anti-social adolescent behavior in the school system. Most of the anti-social behavior was associated significantly more with males, although there were no male/female differences in absconding, disrespecting teachers, verbal abuse, and bad language use. Adolescent boys attending coeducational schools were less anti-social than adolescent boys attending single-sex schools. The survey concluded that coeducational schools most significantly decreased adolescent males' anti-social behavior and single-sex schools most significantly decreased adolescent females' anti-social behavior. The results suggest that coeducational schools should help reduce socially disruptive and violent behavior of both adolescent males and females. (Contains 5 tables and 25 references.) (JDM)