In sexual precocity, premature thelarche and premature pubarche have to be distinguished from pathological forms of precocious puberty. The latter has to subdivided into central precocious puberty and precocious pseudopuberty. Delayed puberty is mostly due to a constitutional delay of puberty which will later result in normal pubertal development. However, pathological forms of delayed puberty have to be considered which result either centrally from disorders of the hypothalamus and the pituitary or peripherally from the ovaries. The diagnostic work-up of the different forms is an essential prerequisite for therapy which can encompass pharmacological suppression and induction of pubertal development.