Life course scholars have established that early life experiences are crucial factors in shaping developmental trajectories. Early adolescent health has been one of the most widely studied of these factors, with increased attention being paid to the enduring effects of obesity across the life course. While obesity is shown to be associated with several negative social and psychological outcomes, less is known regarding how self-perceived weight affects individuals’ mental health trajectories through adolescence and young-adulthood. To address this gap, I use nationally representative longitudinal panel data to analyze how self-perceived weight affects self-esteem trajectories during the transition to adulthood. Furthermore, I test the extent to which these processes work differently for young men and women. Consistent with previous literature, I find that, on average, self-esteem increases linearly through adolescence and young adulthood. While weight perception is significantly and negatively associated with self-esteem trajectories for both men and women, the effect is greater for women than men. These findings are relevant for scholars and health practitioners and, in the conclusion of this article, the implications of these findings are discussed.