This study extends previous research on the social psychological implications of pubertal timing to education by applying a life course framework to data from the National Longitudinal Study of Adolescent Health and from the Adolescent Health and Academic Achievement Study. Early pubertal timing, which has previously been associated with major social psychological changes in girls' lives during middle school, predicted girls' grade point average and probability of course failure at the start of high school. Because of this initial failure during the high school transition, it also predicted their probability of dropping out of high school, and, among those who graduated, their grade point average at the end of high school. Such research demonstrates one way in which the immediate social psychological risk of early pubertal timing, measured as the age at menarche, translates into long-term disadvantage for girls, thereby opening up new avenues of research for social psychologists interested in youth development, health, and education. (Contains 4 tables and 1 footnote.)