Examined third and sixth graders' depression, anxiety, and perceived academic competence every six months for three years. Found that compared to teachers' ratings, boys overestimated and girls underestimated competence. Gender differences emerged in fourth/fifth grade, increasing through eighth grade. Controlling for depression and anxiety eliminated most gender differences in over- and underestimation. Self-reported depression/anxiety predicted changes in tendency to overestimate. (Author/KB)