PURPOSE: The aim of this article was to determine the relationship between gender norms and weight control behaviors in U.S. adolescents. METHODS: We analyzed prospective cohort data from the National Longitudinal Study of Adolescent to Adult Health (N = 9,861), at baseline in 1994-1995 (ages 11-18 years, Wave I), 1-year follow-up (ages 12-19 years, Wave II), and 7-year follow-up (ages 18-26 years, Wave III). The primary exposure variable was a measure of one's gender normativity based on the degree to which males and females behave in ways that are similar to the behaviors of their same-gender peers. The outcome variable was an individual's weight control attempts (trying to lose or gain weight) and behaviors (dieting, fasting/skipping meals, vomiting, or weight-loss pills/laxatives/diuretics to lose weight or ate different/more foods than usual or taking supplements to gain weight). RESULTS: In logistic regression analyses controlling for potential confounders, a higher baseline individual gender normativity score (higher femininity in females and higher masculinity in males) was associated with weight loss attempts (β = .10; p = .01) and weight loss behaviors (β = .18; p < .001) in girls but was associated with weight gain attempts (β = .18; p < .001) and behaviors (β = .16; p < .001) in boys at 1-year follow-up. Higher individual gender normativity score was protective of weight loss attempts (β = -.15; p < .001) and weight loss behaviors (β = -.17; p < .001) in males but not females at 7-year follow-up. Loess plots provided visualizations of significant relationships. CONCLUSIONS: Gender norms may reinforce a thinner body ideal for girls but a larger ideal for boys.