This study examined dominance attempts of grade school children engaged in a cooperative task. Within each of three grade levels (K, 1, 3), eight mixed-sex triads were randomly formed. Utilizing verbal indices of dominance, significant differences were found for cross-sex and same-sex attempts, by grade level and triadic composition. The results for K and grade 1 confirmed previous research which indicated that boys were more dominant than girls and attempted primarily to dominate other boys. However, with age, girls showed increasing verbal assertiveness toward boys as well as toward other girls, and by grade 3, their overall dominance attempts equalled that of boys. Implications of the findings for research in dominance relations are discussed. (Author/MP)