The aim of the present study was to investigate the effectiveness of the Inside and Outside 2 animation on emotional processing, coping styles, and mindfulness in adolescents. The present study was a quasi-experimental study with a pre-test and post-test design with a control group. The statistical population of the study was all first-year female high school students in Marand in the academic year 1403, from which 40 people were selected using the convenience method and randomly assigned to two experimental and control groups (20 people in each group). Three standard questionnaires were used to collect data, including the Bakker et al. (2010) Emotional Processing Questionnaire, the Moss Coping Styles Questionnaire (2004) and the Grikov et al. (2011) Mindfulness Questionnaire, and multivariate analysis of covariance using SPSS version 28 software was used to analyze the data. The findings showed that watching the animation "Inside and Outside 2" led to a decrease in the scores of suppression, avoidance, and symptoms of unprocessed emotions and an increase in the score of emotion control, and their changes were 14.5%, 12.4%, 12%, and 24.4%, respectively, due to the effect of watching the animation "Inside and Outside 2", but the analysis of covariance in the subscale of experiencing unpleasant emotions was not significant (P<0.05). Also, the results of the univariate analysis of covariance in examining the effect of the animation "Inside and Outside 2" on mindfulness show that the participants' mindfulness scores increased (P<0.05) and 11.6% of the changes in this variable were due to the effect of watching the animation "Inside and Outside 2". In addition, the results showed that watching the animation "Inside and Outside 2" led to an increase in the scores of the subscales of coping styles including hopefulness and tendency to deal with problems, seeking guidance and social support, and tendency to deal with emotions, logical analysis, and reduction of rumination and tendency to deny the problem (P<0.05) and their changes were 24%, 24.1%, and 15.2%, respectively, due to the effect of watching the animation "Inside and Outside 2", but the analysis of covariance in the subscales of acceptance, surrender, and inhibition of emotional expression was not significant (P<0.05). Animation therapy is used as a complementary method in child and adolescent psychotherapy. This method will help accelerate and facilitate the treatment process, and the animation "Inside and Outside 2" helps viewers to better understand the complexities of the human mind and emotions by creatively and realistically displaying emotions, especially anxiety.