The present study was conducted to investigate the effectiveness of reality therapy based on choice theory on cognitive fusion and psychological resilience of divorced adolescents with internalized behavioral-emotional disorder. The current study was a semi-experimental application with a pre-test-post-test design with a control group and a two-month follow-up period. The statistical population of the present study was made up of divorced adolescents suffering from internalized behavioral-emotional disorder in the first and second period of secondary education in Asadabad city, Hamadan province in 2022-2023. In this research, 35 adolescent were selected by purposeful sampling and randomly assigned to experimental and control groups. The adolescent in the experimental group received the reality therapy based on choice theory during ten weeks in ten 90-minute sessions. Children and Adolescents Behavioral Inventory (CABI), Cognitive Fusion Questionnaire (CFQ) and Psychological Resilience Questionnaire (PRQ) were used in the present study. The results showed that reality therapy based on choice theory has significant effect on the cognitive fusion (p<0001) and psychological resilience (p<0001) in the divorced adolescents with internalized behavioral-emotional disorder. Based on the findings of the research, it can be concluded that the reality therapy based on choice theory can be used as an efficient method to reduce cognitive fusion and increace psychological resilience of divorced adolescents with internalized behavioral-emotional disorder by focusing on the present and avoiding discussing the past, avoiding criticism and blaming, focusing on how to solve problems and being responsible in family and social relationships.