Precocious puberty (PP) in girls refers to secondary sexual development occurring earlier than the lower end of normal for the onset of puberty. It might be the presenting feature of a serious underlying condition or signify a common variation of normal for which no treatment is necessary. Depending on the source and type of sex steroids involved, clinical findings may indicate exposure to estrogens, androgens, or both. Likewise, the onset of the PP might be gradual or abrupt and the rate of progression is variable. Recent years have witnessed exciting advancements in the understanding of the molecular genetic basis for some forms of PP in girls as well as in the development of additional treatment options. In this review an update on the most commonly encountered causes of PP in girls including their clinical presentation, pathophysiology, diagnosis, and management are provided. Recommendations regarding when to refer, and areas in particular need of additional research are also delineated.