Prior research has emphasized that the average age of puberty is declining for both adolescent males and females, such that earlier pubertal timing is associated with a range of negative mental health outcomes. While direct effects of pubertal timing on psychopathology are well established, this dissertation aims to examine potential factors (i.e. personality traits and neurocognitive mechanisms) that may play an important role in pathways of early pubertal timing effects on adolescent psychopathology.