This chapter comprehensively summarizes the pivotal role of exercise in fostering optimal bone health during adolescence, a critical period for skeletal development and the attainment of peak bone mass (PBM). It delves into the fundamental aspects of bone biology, including its dynamic nature, physiological functions, and continuous regeneration processes. The discussion highlights how adolescence, often referred to as the “bone bank” period, is crucial for establishing long-term skeletal health, with approximately 40% of PBM gained during the 4-year period surrounding peak height velocity (PHV). Meanwhile, this chapter also explores the multifaceted factors influencing adolescent bone growth, categorizing them into modifiable (physical activity, nutrition, hormonal regulation, lifestyle) and non-modifiable (genetics, ethnicity) elements. A significant focus is placed on the mechanical loading induced by weight-bearing exercises, such as running, jumping, and resistance training, and their profound impact on stimulating osteoblast activity, enhancing bone density, and improving architectural integrity. Conversely, the detrimental effects of sedentary habits and non-osteogenic sports are also addressed. Furthermore, the physiological mechanisms underpinning bone development—modeling, remodeling, and ossification—are elucidated, detailing the coordinated actions of osteoblasts, osteocytes, and osteoclasts. The interplay of these processes in shaping bone size, density, and strength in response to mechanical forces and hormonal fluctuations during puberty is thoroughly discussed. This chapter further incorporates findings from key studies, including the Canadian Saskatchewan Pediatric Bone Mineral Accrual Study (PBMAS) and the Bone Mineral Density in Childhood Study (BMDCS), to illustrate patterns of bone mineral accrual and identify periods of increased fracture risk in adolescents. Ultimately, this chapter underscores the imperative of targeted exercise interventions during adolescence as a non-pharmacological strategy to maximize PBM, mitigate the risk of osteoporosis and fractures in later life, and promote enduring skeletal well-being.