Background: Obesity in adolescence has been increasing in the past several decades. Beverage habits among adolescents include increased consumption of sugar-sweetened beverages and decreased consumption of milk. Objective: This study aimed to examine the association between beverage consumption and 5-y body weight change in 2294 adolescents. Design: Project EAT (Eating Among Teens) is a 5-y longitudinal study of eating patterns among adolescents. Surveys were completed in 1998-1999 (time 1) and in 2003-2004 (time 2). Multivariable linear regression was used to examine the association between beverage consumption at time 2 and change in body mass index from time 1 to time 2, with adjustments for age, socioeconomic status, race, cohort, physical activity, sedentary behavior, coffee, tea, time 1 body mass index, and beverage variables. Results: In prospective analyses, consumption of beverages was not associated with weight gain, except for consumption of low-calorie soft drinks (positive association, P = 0.002) and white milk (inverse association, P = 0.03), but these associations did not appear to be a monotonic linear dose-response relation. The positive association with low-calorie soft drinks was no longer present after adjustment for dieting and parental weight-related concerns, which suggests that the use of low-calorie soft drinks is a marker for more general dietary behaviors and weight concerns. Conclusions: We showed no association between sugar-sweetened beverage consumption, juice consumption, and adolescent weight gain over a 5-y period. A direct association between diet beverages and weight gain appeared to be explained by dieting practices. Adolescents who consumed little or no white milk gained significantly more weight than their peers who consumed white milk. Future research that examines beverage habits and weight among adolescents should address portion sizes, adolescent maturation, and dieting behaviors.