This study examined the role of both pubertal and social transitions in the emergence of gender differences in depressive symptoms during adolescence. This study generated the following findings: (a) Gender differences in depressive symptoms emerged during 8th grade and remained significant through 12th grade. (b) Pubertal status in 7th grade was related to adolescent depressive symptoms over time. (c) Early-maturing girls represented the group with the highest rate of depressive symptoms. (d) Depressive symptoms measured in 7th grade predicted subsequent symptom levels throughout the secondary school years. (e) Recent stressful life events were associated with increased depressive symptoms. (f) Early-maturing girls with higher levels of initial symptoms and more recent stressful life events were most likely to be depressed subsequently. The findings demonstrate the importance of the interaction between the pubertal transition and psychosocial factors in increasing adolescent vulnerability to depressive experiences.