Recent studies have suggested that the age of pubertal onset in children is occurring earlier than previously reported. The precise trigger for the onset of puberty is not known, but it is believed to be a complex interaction between genetics, hormones, and environmental influences. Endocrine disruptors are natural or synthetic environmental chemicals that may result in adverse health by disturbing normal endocrine function through agonistic or antagonistic actions. Endocrine disruptors may result in an altered hormonal status through interference with cell signaling pathways or altering the action of hormone receptors as coactivators or corepressors (1). Several agents have been classified as endocrine disruptors, including phytoestrogens, topical and natural estrogens, pesticides, industrial chemicals, and phthalates. The potential role of endocrine disruptors in reproductive development has been a controversial topic since the early 1990s (2). Although there is a paucity of definitive data to support a role for endocrine disruptors in disturbing the onset and timing of human puberty, several environmental factors may putatively play a role. In this chapter, we discuss the compounds that have been implicated in altering the age of normal puberty, the role of these potential endocrine disruptors in pubertal development, and the implications in genital and reproductive function.