Puberty is the result of a dynamic interaction between genetic factors and environmental cues, all of which lead to the attainment of reproductive capacity. Thus, significant changes in hormone secretion occur from the pre-pubertal to the pubertal stage. The objective of this review is to provide an update of some endocrine, physiological, metabolic and genetic concepts involved in the establishment of the hypothalamic-hypophyseal-gonadal axis function promoting the onset of the reproductive function during puberty. To achieve this purpose, basic aspects of the function of the hypothalamic-hypophyseal-gonadal axis, the control of the axis by neurotransmitters and the interaction between reproductive function and metabolic status will be considered. Finally, the role of the novel kisspeptin system and the GPR54 receptor as modulators of puberty will be considered, in addition to the hierarchical expression of the main genes acting as regulators of the onset of puberty.