Objective: This study investigated whether a universal school-based life skills program--IPSY (Information + Psychosocial Competence = Protection)--against substance misuse exerted the same effectiveness for young adolescents (10.5-13 years) from distinct alcohol use trajectories characterized by late childhood risk factors (temperament, self-worth, social problems with peers). Method: Analyses were based on a German sample of school students (N = 1,484). A longitudinal quasi-experimental design (intervention/control) with schoolwise assignment to the respective groups was used. Data were gathered via self-report questionnaire. Two-part growth mixture modeling was applied. Results: Two prototypical trajectory classes of early alcohol use were found: a problematic group with a sharp increase in prevalence and quantity of consumed alcohol (19.7%) and a normative group with a moderate increase in both outcomes (80.3%). The problematic trajectory class was associated with several risk factors. IPSY decreased the likelihood of membership in the problematic group. Furthermore, IPSY buffered the increase in prevalence and quantity for the normative group, whereas it had no effects on these indicators for the problematic group. Concerning quantity of alcohol use, the effect size in terms of a difference in estimated means between intervention and control group at the last measurement point in the normative group was d = 0.33 (95% CI [0.21, 0.44]). Conclusions: Study findings indicate the usefulness of IPSY for reducing alcohol use especially in normative developing adolescents. However, the minority of adolescents consistently pursuing a problematic developmental pathway of alcohol use seem to be in need of earlier, more tailored treatments. (Contains 8 footnotes, 5 tables, and 3 figures.)