Objective: This study aims to evaluate the effectiveness of an anti-bullying intervention carried out with adolescents from public schools. Methods: A longitudinal, quasi-experimental design was used, with pre-test and immediate post-test evaluations. A sociodemographic questionnaire, Cartoon Test, KIDSCREEN-52, and Social Support Appraisals were used. The intervention had four editions and consisted of eight weekly meetings, amounting to 16 hours. A total of 69 adolescents (12-17 years) participated in the study, 40 of which were allocated to the Experimental Group and 29 to the Control Group. Results: After the intervention, the Experimental Group demonstrated improvements in the adolescents’ perception of bullying, quality of life, and social support. The intergroup analysis indicated a better perception of bullying for the Experimental Group. Conclusion: From the data, it can be concluded that the intervention demonstrated its effectiveness and has the potential to be replicated in the school context.