An accumulation of research evidence suggests that early pubertal timing plays a significant role in girls' behavioral and emotional problems. If early pubertal timing is a problematic event, then early developing Black girls should manifest evidence of this crisis because they tend to be the earliest to develop compared to other girls from different racial and ethnic groups. Given the inconsistent findings among studies using samples of Black girls, the present study examined the independent influence of perceived pubertal timing and age of menarche on externalizing behaviors and depressive symptoms in a nationally representative sample of Black girls (412 African American and 195 Caribbean Black; M = 15 years). Path analysis results indicated that perceived pubertal timing effects on externalizing behaviors were moderated by ethnic subgroup. Caribbean Black girls' who perceived their development to be early engaged in more externalizing behaviors than Caribbean Black girls' who perceived their development to be either on-time or late. Age of menarche did not significantly predict Black girls' externalizing behaviors and depressive symptoms. The onset of menarche does not appear to be an important predictor of Black girls' symptoms of externalizing behavior and depression. These findings suggest ethnic subgroup and perceived pubertal timing are promising factors for better understanding the adverse effects of early perceived pubertal timing among Black girls. © 2010 Springer Science+Business Media, LLC.