Life stages are typically classified into five stages: childhood, adolescence, early adulthood, middle adulthood, and late adulthood (Super DE, Career choice and development: applying contemporary theories to practice, 2nd edn. Jossey-Bass, pp 197-261, 1990), and the environment surrounding individuals changes with their life stages. Although physical growth commences in the fetal stage, it proceeds postnatally through successive developmental phases, including infancy, early and middle childhood, adolescence, and adulthood. The stage of adolescence is an important phase in human life during which individuals experience both physical and psychological changes. Preventing stunted growth and development in adolescents is essential for fostering healthy adults. This chapter outlines the stages and characteristics of adolescence. The terms "growth" and "development" are used widely. In this chapter, the "growth" is defined as the quantitative changes, specifically increases in the mass or length of bodily components. In contrast, the term "development" refers to qualitative changes, such as the functional enhancement of various bodily organs.