<![CDATA[Bullying remains a significant behavioral and psychosocial concern among adolescents and requires interventions addressing both maladaptive cognitions and moral development. This study examined changes in students' bullying behavior following REBT-based group counseling integrated with Islamic educational values. A quantitative one-group pretest–posttest design was employed with 25 students selected purposively from 115 screened students at SMKN 2 Painan, West Sumatra, Indonesia. Participants received six group counseling sessions based on the REBT ABCDEF framework, integrated with Islamic values including ukhuwah, rahmah, 'adl, amanah, and akhlāq al-karīmah. Bullying behavior was assessed using a 32-item scale covering physical, verbal, and relational dimensions. Data were analyzed using descriptive statistics, the Shapiro–Wilk test, paired-samples t-tests, and Cohen's dz. The mean overall bullying score decreased from 125.84 (SD = 2.23) at pretest to 95.16 (SD = 5.63) at posttest, representing a 30.68-point reduction. The difference was statistically significant, t(24) = 28.42, p .001, with a very large within-group effect (dz = 5.68). Significant reductions were also observed in physical, verbal, and relational bullying. The integrated counseling approach was associated with substantial reductions in bullying behavior and shows promise as a contextually responsive school counseling intervention. Controlled and longitudinal studies are needed to establish causal effectiveness and sustainability.Keyword: Bullying behavior; REBT; group counseling; Islamic educational values; adolescents]]>
