Precocious pubertal development is generally defined as the clinical manifestation of secondary sex characteristics above the 99.6th centile for age. In the UK this corresponds to 8 years in girls and 9 years in boys. The UK growth charts divide at these ages to remind us that a child who plots on the left sided panel and who has pubertal signs is precocious and warrants medical review. The vertical puberty lines have reminders of precocity (and delay). Stage lines on the RCPCH 2-20 year specialist childhood and puberty close monitoring growth chart can determine the centile at entering each of the Tanner stages and menarche and also aid in monitoring the pace of pubertal development. Sometimes the pace can be over-rapid and thus warrant investigation itself. In a tall, early pubertal developing child, the upper 99.6th centile line and its left sided boundary can help decide whether the growth and pubertal progress is precocious. Some children, especially girls with dark hair may present with precocious pubarche. Differentiating this from serious adrenal disorders is usually straightforward on follow up. True early thelarche may not be of concern in toddlers and in tall early maturers. The differential process from pathological precocious puberty will be discussed. The absence of benefit of over-treating early normal developers may be associated with a risk of PCOS. However severe behavioural disturbance may be an indication to treat. Rapid onset and progress through puberty can be seen in children with central disorders both congenital or acquired, and those born SGA. This requires careful tracking and intervening earlier rather than later with a GnRH analogue may produce a significant gain in pubertal height and prevent the loss due to premature epiphyseal fusion.