The current study aimed to describe adolescents' social class and self-concept at the "Khatulistiwa Berbagi” learning house. The present study used mixed methods combining quantitative and qualitative approaches. The data collection was conducted during the even semester in the academic year of 2022/2023, with 22 marginalized adolescents participating. All participants come from a family with a monthly income of up to IDR 1.800.000 (lower social class). Social class data was gathered using Interviews, observation and documentation studies. While data regarding self-concept was collected using the Tennessee Self-Concept Scale (TSCS). The current research used descriptive statistics and triangulation as data analysis techniques. The study's results found that parents' socio-economic class has a significant relationship with the formation of self-concept images of marginal adolescents. As a whole, the findings of this study revealed that 73.66% of the self-concept of marginalized adolescents is in the highly negative category. A negative self-concept is associated with the inability to control one's emotions and tends to have deviant behavior. Collaborative activities between parents, teachers, counselors, psychologists, and social welfare institutions are recommended to achieve the self-concept developmental milestone of marginalized adolescents.