Objective: This investigation tested whether the timing of puberty continued to be associated with experiences of psychopathology (symptoms and disorders) from mid-adolescence into young adulthood. Method: At age 24, 931 participants from a large community sample, who had been interviewed twice during adolescence, completed a telephone interview (assessing Axis I disorders and elevated antisocial and borderline personality traits) and a mailed questionnaire battery. Results: Analyses tested whether pubertal timing was associated with lifetime and current history of mental disorders and psychosocial functioning in young adulthood. As expected, young women who had been early maturers had higher rates of lifetime history of disorder along with current elevation of psychosocial symptoms compared with women who were on-time maturers. Young men who had been late maturers, compared with other men, had elevated onset of disruptive behavior and substance use disorders during the transition to adulthood. Conclusions: Early maturing females are at unique risk of persistent difficulty during adolescence and should be targeted for preventive efforts. Late maturation among males may be associated with a late-onset pathway for deviant behavior or substance abuse. J. Am. Acad. Child Adolesc. Psychiatry, 2004;43(6):718-726. Key Words: pubertal timing, depression, antisocial personality, social supports.