<![CDATA[Corruption remains a critical behavioral and psychological challenge in Indonesia, with its roots increasingly linked to deficiencies in adolescent moral development. However, empirical evidence regarding counseling-based preventive interventions within secondary school settings remains limited. This study examines the effectiveness of a structured counseling intervention in fostering anti-corruption character among secondary school students in Indonesia. The research used a quantitative quasi-experimental design with a pre-test and post-test control-group approach. Purposive sampling selected 60 participants, who were equally assigned to an experimental group (n = 30) that received eight sessions of structured group counseling and a control group (n = 30) that followed the standard school guidance program. Data were collected using a validated 45-item Likert-scale instrument based on nine anti-corruption values developed by the Komisi Pemberantasan Korupsi (KPK). Statistical analysis using IBM SPSS Statistics Version 26 indicated a significant improvement in the experimental group (t(29) = 24.83, p < .001, Cohen’s d = 4.62), while no significant change was observed in the control group. Follow-up assessments further confirmed the sustainability of the intervention effects. These findings show that structured counseling is an empirically supported, psychologically grounded strategy for strengthening anti-corruption character in Indonesian secondary education contexts. Keywords: anti-corruption character, character education, counseling intervention, secondary school students, Indonesia]]>
