Designing effective educational measures constitutes a key area of action for achieving global sustainability goals. Therefore, the present study examined a training addressing sustainable consumption practices in plastic reduction, fashion and food. An interactive training was held in a German comprehensive high school with grade 11 students, addressing psychological drivers of sustainable consumption behavior, namely, awareness and knowledge, emotional, rational and value-based factors. The training was evaluated in a pretest(t1)/posttest(t2)/follow-up(t3) design. Final self-report data was obtained from 77 pupils in t1 and t2 and 56 pupils for all three points of measurement. Results of a repeated measures MANOVA indicate significantly higher levels of all outcome variables directly after the training. Significant long-term effects emerge on the knowledge of sustainable consumption alternatives, anticipated feelings of guilt, perceived norms in the individual's social environment, perceived control over one's own behavior, as well as sustainable consumption behavior in everyday life. Taken together, results suggest the training to be an effective instrument for furthering actual sustainable consumption practices of young pupils. Its implementation during school hours with regular-sized classes offers a low expenditure educational approach for sustainable consumption.