A quasi-experimental pretest/posttest study using a control group was conducted to investigate the effects of EQUIP for Educators--implemented as a universal prevention program--on prevalence of antisocial behavior, attitude towards antisocial behavior, self serving cognitive distortions, and moral judgment of young adolescents. Participants were 764 students (present at both waves: N experimental group = 512, N control group = 110) from nine prevocational secondary schools in the Netherlands (M age = 14.07, SD = 0.60). Repeated measures were used to examine intervention effects. Students in the experimental group reported a significant reduction of both attitude towards antisocial behavior and self serving cognitive distortions compared to students within the control group. Ethnicity appeared to play a moderating role; effects on both attitude towards antisocial behavior and self-serving cognitive distortions were only significant for students with a Dutch ethnic background. (Contains 4 tables and 2 figures.)