The present study was conducted to investigate the comparing the effectiveness of quality of life therapy and unified protocol for transdiagnostic treatment on isolation and alexithymia in adolescents with symptoms of internet addiction. 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 adolescents with symptoms of Internet addiction in Isfahan city in the academic year of 2023-2024, who were studying in the second period of secondary school. In this research, 49 adolescent with symptoms of Internet addiction were selected by purposeful sampling and randomly assigned to experimental and control groups. internet Addiction Scale (IDS), Isolation Questionnaire (IQ) and Alexithymia Questionnaire were used in the present study. The results showed that quality of life therapy and unified protocol for transdiagnostic treatment have significant effect on the isolation and alexithymia in adolescents with symptoms of Internet addiction. The results of the follow-up test also showed that there was no significant difference between the effectiveness of the present interventions in the isolation variable. However, in the alexithymia variable, unified protocol for transdiagnostic treatment was more effective than quality of life therapy.