Puberty is characterized by gonadarche and adrenarche. Gonadarche represents the reactivation of the hypothalamic-pituitary-gonadal axis with increased gonadotropin-releasing hormone, luteinizing hormone, and follicle-stimulating hormone secretion following the quiescence during childhood. Pubarche is the development of pubic hair, axillary hair, apocrine odor reflecting the onset of pubertal adrenal maturation known as adrenarche. A detailed understanding of these pubertal processes will help clarify relationships between the timing of the onset of puberty and cardiovascular, metabolic, and reproductive outcomes in adulthood. The onset of gonadarche is influenced by neuroendocrine signals, genetic variants, metabolic factors, and environmental elements.