Many problems occur at the age of adolescence, especially mental health disorders. Teens experiencing life changes could be at risk for mental health disorders. Adolescents with flourishing/good mental health can become adults who are optimistic, independent, creative, and able to adequately contribute to their surroundings by optimally using their capacities. This study aims to describe an overview of the psychological, emotional, and social well-being of adolescents; thus, it can be used to create a national picture of adolescents' mental health in Indonesia. This is a descriptive study with a cross-sectional design. The study sample included 972 adolescents in grades 7 and 8 in public and private junior high schools in Depok, Jakarta, Tangerang, and Denpasar who were selected by stratified random sampling. Adolescents possess a high degree of psychological, emotional, and social well-being, and 46.3% of the adolescents were discovered to have flourishing mental health while the others had moderate and languishing/weak mental health. It is necessary to maintain and enhance the involvement of adolescents' support systems to maintain their mental health. Moreover, adolescents should explore their potential in order to learn adaptive coping mechanisms to help them solve problems appropriately.