This study reports on relationships among gender, maternal depressed mood, and children's trajectories of depressive phenomena across middle childhood and early adolescence. It tested the hypothesis that, compared to boys, girls become increasingly vulnerable to maternal depression as they enter adolescence. The study sample consisted of 834 families from 10 Pacific Northwest schools that participated in the Raising Healthy Children project. Maternal depressed mood and children's depressive phenomena were assessed annually during an 8-year period that spanned Grade 3 through Grade 10 for the children. Mean scores for girls' depressive phenomena increased relative to those for boys as children matured. Maternal depressed mood was significantly and positively associated with children's level of depressive phenomena. An interaction effect of gender and maternal depressed mood on acceleration in children's depressive phenomena indicated that girls' trajectories of depressive phenomena were sustained in the presence of maternal depression while those of boys declined in the presence of maternal depression.