The present study aimed to determine the effectiveness of Acceptance and Commitment Therapy (ACT) on the emotional schema of shame and emotional expressivity in adolescent boys with high social anxiety in District 13 of Tehran. This study employed a quasi-experimental design with a pretest–posttest and follow-up design with a control group. The statistical population consisted of all male students in the first and second levels of secondary school with high social anxiety in the 2025–2026 academic year. Using a multistage cluster sampling method, 30 students whose scores on the Social Anxiety Questionnaire were above the cutoff point were selected and randomly assigned to an experimental group (n = 15) and a control group (n = 15). The research instruments included the Leahy Emotional Schema Scale (2002), the Emotional Expressivity Scale (King & Emmons, 1990), and the Social Anxiety Questionnaire (Connor et al., 2000). The experimental group received Acceptance and Commitment Therapy in eight 120-minute sessions, whereas the control group received no intervention. Data were analyzed using repeated-measures analysis of variance in SPSS version 26. The results indicated that the effects of time, group, and the interaction between time and group on the dependent variables were statistically significant . Furthermore, Acceptance and Commitment Therapy led to a significant and sustained reduction in the emotional schema of shame and a significant increase in emotional expressivity in the experimental group compared with the control group at the posttest and follow-up stages. Based on the findings, Acceptance and Commitment Therapy can be considered an effective intervention for reducing the emotional schema of shame and improving emotional expressivity in adolescents with social anxiety.
