AbstractPurpose To evaluate the longitudinal relationship between obesity during adolescence and development of disability during young adulthood. Methods A cohort of 8,032 individuals aged 11–21 years enrolled in 1994–1995 (Wave I) of the National Longitudinal Study of Adolescent to Adult Health, followed up in 1996 (Wave II) and in 2001–2002 (Wave III). Individuals were divided into four categories based on weight and height of Wave II and Wave III: (1) developing obesity; (2) persistent obesity; (3) no obesity; and (4) obesity reversal. Disability was measured in Wave III using a measure of functional limitations and the Short Form 36 physical functioning scale. Logistic regression was used to predict the probability of disability as a function of weight category. Results Compared with their nonobese peers, adolescents developing obesity (adjusted odds ratio: 1.83 [95% confidence interval: 1.51–2.22]) and with persistent obesity (adjusted odds ratio: 2.09 [95% confidence interval: 1.64–2.67]) had a higher odds of having a functional limitation in Wave III. Conclusions Developing obesity and persistent obesity during adolescence were significantly associated with increased disability in young adulthood.