School defi cit is considered a risk factor for the development of antisocial behavior. This study assessed the effi cacy of individual program on academic skills for adolescents admitted to juvenile detention. The sample consisted of 18 adolescents, nine who received the intervention (experimental group) and nine in the control group. The schooling activities were developed in a range of 12 to 18 weeks with two to four hours per week and effi cacy was measured by School Performance Test (SPT) that evaluates writing, reading and arithmetics. The results of the comparison between pretest and post-test showed a statistically signifi cant increase in the experimental group's math skills (Z =-2.673, p = .008) and overall score (Z =-2.549, p = .012). Calculated via the STP the average educational lag at the time of the pretest was 8.3 years for the experimental group and 8.9 years for the control group. Subsequent to the intervention, the average lag dropped to 7.3 years for the experimental group and remained to 8.6 years for the control group. This intervention proved to be a promising technique to reduce academic defi cits in adolescents from juvenile detention.