Background and Study Aim. Adolescence is characterized as a critical stage in the development of health-related habits, whose importance extends beyond this period, as they predict health-related behaviors in adulthood. The main objective of this study was to analyze differences in body mass index, physical self-concept, and self-confidence of adolescent boys and girls. Materials and Methods. This is a comparative research. The population in this study was adolescents aged 13-19 years with a random sampling technique of 94 people (male 53, female 41). Inclusion criteria for adolescent students in this study include the absence of any disease-related limitations. The instruments used were Body Mass Index, Physical Self-Perception Profile (PSPP), and a self-confidence questionnaire. The statistical analysis technique used the Statistical Package for Social Science (SPSS) version 21 software. The level of statistical significance was set at p-value < 0.05. Results. The results of the analysis showed that: (1) Body Mass Index of adolescent girls is higher than boys (p-value < 0.05). (2) Physical Self-Concept of adolescent girls is higher than that of boys (p-value < 0.05). (3) Self-Confidence of adolescent boys is better than that of girls (p-value < 0.05). Conclusions. The results of this study are expected to be a guideline for schools and health agencies to pay attention to the psychological health conditions of adolescents. Adolescents are expected to improve their body image with a confident attitude in order to avoid psychological problems.