This study examined depression in low-income elementary school children and identified gender differences in factors that influence depression from an ecological perspective. Participants were 262 first- to sixth-grade children recruited from six Korean community centers. Personal factors were anxiety and self-concept. Environmental factors consisted of caregiver (perceived caregiving style), school (perceived school life and quality of peer relations), and neighborhood. The outcome variable was depression. The predictors of boys' depression were anxiety, perceived school life, and neighborhood. Predictors of girls' depression were anxiety, self-concept, caregiving style, and neighborhood. School nurses are encouraged to screen elementary school children for depressive symptoms and consider gender differences and environmental factors when intervening in depression. School-focused interventions may be more effective for boys; family-focused interventions may be more beneficial for girls.