Adler emphasized social interest as a social adaptive lifestyle. The study used a nudge strategy to generate social interest in middle school students through a volunteer program. If student gets a good reward for volunteering, it can be a nudge naturally toward social interest. The dependent variables for the volunteer program as a nudge are inferiority complex, social interest, and game over-immersion. Using convenience sampling, it was assigning 28 participants to two groups each. The experimental group participated in an intervention consisting of 9 sessions of 90 min each, once a week. Both groups were assessed before and after intervention and at a 4-weeks follow-up. Program effectiveness was analyzed using repeated measures analysis of variance. The results showed that it was a significant difference in inferiority complex between the experimental and control groups immediately after intervention, and that it was a strong difference in social interest and game over-emersion both immediately after the experiment and 4 weeks later. Therefore, it proposes that volunteer programs to increase social interest and transition to a pro-social lifestyle be included as a nudge in school extracurricular activities or curriculum.