Recent research suggests that rumination may represent both a risk factor for and consequence of depression, especially among female samples. Nevertheless, few longitudinal studies have examined a reciprocal model of rumination and depression in early adolescence, just before rates of depression diverge by gender. The present study evaluated a cross-lagged path model of rumination and depression in a sample of 408 early adolescents. Gender moderation was also examined. Support was found for a longitudinal bidirectional model of rumination and depression but only among girls. For boys, increased rumination emerged as a consequence, not as a predictor, of depression symptoms. In early adolescence, rumination may be a greater risk factor for depression among girls than boys, whereas depression may be a significant vulnerability factor for increased rumination among both boys and girls. Why rumination may be more maladaptive for girls than boys is discussed within a psychosocial and developmental framework.