Abnormal functioning of the hypothalamic-pituitary-adrenal (HPA) axis, a critical mammalian stress response system, has been associated with emotional responses such as anxiety and depression, as well as with behavioral and cognitive processes such as aggression, learning and memory deficits, and failure of response inhibition. This review examines the evidence for HPA axis dysregulation related to childhood maltreatment. It is concluded that child maltreatment may lead to disruptions in HPA axis functioning, and that factors such as age of maltreatment, parental responsiveness, subsequent exposure to stressors, type of maltreatment, and type of psychopathology or behavioral disturbance displayed may influence the degree and patterning of HPA disturbance.