This study examines gender differences in the development of dieting among a representative sample of 1,368 Norwegian boys and girls. The respondents were followed over 3 time points from ages 13/14 to 20/21. Latent growth curve analyses were conducted showing that girls' dieting scores increased while boys' scores remained constant. Gender differences in the development of dieting could be explained neither by differences in the development of appearance dissatisfaction nor by changes in relation to parents. In contrast, the dieting differences between boys and girls could be partially explained by a greater increase in emotional problems among girls compared with boys. Further research is needed, targeting in particular younger age groups, in order to acquire knowledge on whether appearance dissatisfaction serves as mediator of gender differences in dieting at other ages.